A new script is introduced, linux_perf_report.py, which reads Linux perf
data collected when running with FLAG_perf_basic_prof enabled and
produces an input file for flamegraph.pl, or a report of the hottest
bytecode handlers.
The bottom blocks of the produced flamegraph are bytecode handlers.
Special bottom blocks exist as well for compile routines, time spent
outside the interpreter and interpreter entry trampolines.
Because various Stubs and other pieces of JITted code do not maintain the
frame pointer, some sampled callchains might be incomplete even if V8 is
compiled with no_omit_framepointer=on. The script is able to detect the
most common anomaly where an entry trampoline appears in a chain, but not
on top, meaning that the frame of another bytecode handler is hidden. In
this case, the sample will be moved to a [misattributed] group to avoid
skewing the profile of unrelated handlers.
Misattributed samples and compilation routines are hidden by default.
BUG=v8:4899
LOG=N
Review URL: https://codereview.chromium.org/1783503002
Cr-Commit-Position: refs/heads/master@{#35574}
This introduces a compiler pass that schedules the graph and re-wires effect chain according to the schedule. It also connects allocating representation changes to the effect chain, and removes the BeginRegion and EndRegion nodes - they should not be needed anymore because all effectful nodes should be already wired-in.
This is an intermediate CL - the next step is to move lowering of the Change*ToTaggedEffect nodes to StateEffectIntroduction so that we do not have to introduce the effectful versions of nodes.
Review URL: https://codereview.chromium.org/1849603002
Cr-Commit-Position: refs/heads/master@{#35565}
- Get rid of fixing up pointers on the main thread
- Get rid of sweeping on the main thread
Instead:
- Record (and process afterwards) slots in parallel
- Add the pages to the concurrent sweeper as pointers have already been fixed
This reverts commit 6df04b296b.
BUG=chromium:581412
LOG=N
TEST=cctest/test-compaction/*
Review URL: https://codereview.chromium.org/1891683002
Cr-Commit-Position: refs/heads/master@{#35485}
Fixes for misnamed toolchain from https://github.com/appcelerator/v8_titanium.
Added a way to specify the NDK path since the Mac versions of the NDK aren't checked into the tools repo.
Disabled a few dependencies which do not build on the Mac but which aren't needed for building usable V8 static libraries.
Made the including of libdl and librt omitted for Mac hosted builds.
BUG=
Review URL: https://codereview.chromium.org/1879793002
Cr-Commit-Position: refs/heads/master@{#35456}
This change implements switch as a balanced if/else tree or break table or
hybrid. A lot of asm.js modules are expected to extensively use switch
alongside function tables that can benefit from a better implementation.
BUG=v8:4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,bradnelson@chromium.org,ahaas@chromium.org
LOG=N
Review URL: https://codereview.chromium.org/1838973002
Cr-Commit-Position: refs/heads/master@{#35455}
Despite man page documentation:
-f Display the symbol table of a dynamic library flat (as one
file not separate modules).
`nm` on mac treats `-f` as a shorthand for `-format`. The `-f` argument
does not seem to be required, so just remove it completely.
(For `-format` documentation - see `nm --help` on mac).
BUG=
Review URL: https://codereview.chromium.org/1840633002
Cr-Commit-Position: refs/heads/master@{#35445}
A new script, bytecode_dispatches_report.py reads the table produced
when FLAG_trace_ignition_dispatches is enabled and produces either a
report of top source-destination pairs, or a heatmap that can be
viewed interactively and saved to file.
BUG=v8:4899
LOG=N
Review URL: https://codereview.chromium.org/1869423002
Cr-Commit-Position: refs/heads/master@{#35438}
Check if a previous run left an inconsistent state behind.
The check is right before trying to push a new state as then
all information is available, like commit message and tag
name.
This is still only a band-aid. If gnumbd is down for a
longer period, an unprocessed commit won't be found, but
the push attempt will still fail.
Review URL: https://codereview.chromium.org/1887583002
Cr-Commit-Position: refs/heads/master@{#35437}
The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:
- Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
- Uses it appropriately.
- Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
- Fixes a bunch of incorrect formats.
Original CL: https://codereview.chromium.org/1869433004
Reverted in: https://codereview.chromium.org/1867383002
Reverted again in: https://codereview.chromium.org/1877823003
Reverts due to non-CQ bots:
- First: v8_win_dbg, v8_win64_dbg, v8_mac_dbg
- Second: gc mole (added to v8_linux_rel_ng for this patch)
R= jochen@chromium.org
TBR= ahaas@chromium.org,bmeurer@chromium.org,yangguo@chromium.org
Review URL: https://codereview.chromium.org/1872203005
Cr-Commit-Position: refs/heads/master@{#35423}
This removes the "AboutToRun" callback. It makes not much
sense as it is not actually called before a test is run,
but just before the results are retrieved from the results
queue. Therefore, from an information-value p-o-v it is
redundant to the "HasRun" callback.
This also reduces log size on the bots by 50%, in order to
reduce buildbot slowness, which is tied to the amount
of logs.
Review URL: https://codereview.chromium.org/1874973003
Cr-Commit-Position: refs/heads/master@{#35382}
Reason for revert:
One small issue easily fixed here: https://codereview.chromium.org/1867333003/
But it looks like MSVS 2013 doesn't like some of the formats and exists with the unhelpful:
Stderr:
f:\dd\vctools\crt\crtw32\stdio\output.c(1125) : Assertion failed: ("Incorrect
format specifier", 0)
It's easier to revert for now, I'll dig more into the docs:
https://msdn.microsoft.com/en-us/library/56e442dc(v=vs.120).aspxhttps://msdn.microsoft.com/en-us/library/tcxf1dw6(v=vs.120).aspx
And then resubmit, making sure I run these bots.
Original issue's description:
> Fix printf formats
>
> The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:
>
> - Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
> - Uses it appropriately.
> - Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
> - Fixes a bunch of incorrect formats.
>
> R= jochen@chromium.org, bmeurer@chromium.org, yangguo@chromium.org, ahaas@chromium.org
>
> Committed: https://crrev.com/6ebf9fbb93d31f9be41156a3325d58704ed4933d
> Cr-Commit-Position: refs/heads/master@{#35365}
TBR=jochen@chromium.org,bmeurer@chromium.org,yangguo@chromium.org,ahaas@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review URL: https://codereview.chromium.org/1867383002
Cr-Commit-Position: refs/heads/master@{#35366}
The usage of __attribute__((format(x, y)) was either wrong or missing from multiple functions, leading to erroneous formats. This CL:
- Imports PRINTF_FORMAT macro from Chrome's src/base/compiler-specific.h.
- Uses it appropriately.
- Imports Chrome's base/format_macros.h mainly to fix size_t formats (further cleanup could be done).
- Fixes a bunch of incorrect formats.
R= jochen@chromium.org, bmeurer@chromium.org, yangguo@chromium.org, ahaas@chromium.org
Review URL: https://codereview.chromium.org/1869433004
Cr-Commit-Position: refs/heads/master@{#35365}
This will allow the infrastructure to warn about new very
slow tests which are not marked as slow. If not marked, they
might be scheduled late in the test run and prolong the
overall running time uselessly.
BUG=chromium:601468
LOG=n
Review URL: https://codereview.chromium.org/1863793005
Cr-Commit-Position: refs/heads/master@{#35356}
The slow_archs list had only an effect when no timeout was
passed. Now it will also increase the timeout on the bots.
Also simplified the code a bit.
Review URL: https://codereview.chromium.org/1866953002
Cr-Commit-Position: refs/heads/master@{#35355}
1) I moved the implementations of the wrapper functions into a new cc
file so that I can use these wrapper functions in tests.
2) I made a generic test for all tests in
test-run-calls-to-external-references.cc. In the new test we only
compare the result of a function call through an external reference with
the result of a direct function call. This is sufficient because we only
want to test function calls through external references work here.
The implementation of these functions are tested somewhere else.
R=titzer@chromium.org
Review URL: https://codereview.chromium.org/1853123002
Cr-Commit-Position: refs/heads/master@{#35289}
Introduce a ResumeGeneratorTrampoline, which does the actual stack state
reconstruction (currently always restores a fullcodegen frame), and
introduce appropriate TurboFan builtins for %GeneratorPrototype%.next,
%GeneratorPrototype%.return and %GeneratorPrototype%.throw based on
this native builtin.
Also unify the flooding in case of step-in to always work based on
JSFunction and remove the special casing for JSGeneratorObject.
R=mstarzinger@chromium.org, neis@chromium.orgTBR=rossberg@chromium.org
BUG=chromium:513471
LOG=n
Review URL: https://codereview.chromium.org/1865833002
Cr-Commit-Position: refs/heads/master@{#35283}
We expect that the majority of malloc'd memory held by V8 is allocated
in Zone objects. Introduce an Allocator class that is used by Zones to
manage memory, and allows for querying the current usage.
BUG=none
R=titzer@chromium.org,bmeurer@chromium.org,jarin@chromium.org
LOG=n
TBR=rossberg@chromium.org
Review URL: https://codereview.chromium.org/1847543002
Cr-Commit-Position: refs/heads/master@{#35196}
Change x64 to use the external references like all other platforms.
BUG=chromium:581076
LOG=N
Review URL: https://codereview.chromium.org/1844283002
Cr-Commit-Position: refs/heads/master@{#35160}
Test case objects were sorted without key function, resulting
in random sort order. On sharded builds, the shards are
determined by the sort order and rely on a deterministic
sorting. This led to random cctest and unittest cases being
dropped or executed twice on sharded testers.
TBR=jkummerow@chromium.org, hablich@chromium.org
Review URL: https://codereview.chromium.org/1842673002
Cr-Commit-Position: refs/heads/master@{#35151}
Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.
Just like --perf-basic-prof, the file writer is not synchronized (even worse, there is a per-isolate file handle), so we will run into trouble with multiple isolates. However, this patch is still an improvement on --perf-basic-prof, and it should be fine to replace ll-prof.
The patch also introduces experimental support for debug info, but it does not seem to be picked by the perf tool.
Usage:
You need the perf tool from Linux kernel >4.5. Then run:
$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted
Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic clock for perf sample timestamping. The "perf inject -j" command injects the collected code events into the perf data file, writing the output into perf.data.jitted. The perf report command then creates the report.
Review URL: https://codereview.chromium.org/1809203007
Cr-Commit-Position: refs/heads/master@{#35091}
It's been on since M49. Also moved tests from harmony -> es6,
one of which was merged with another test of the same name.
While moving stuff over to regexp.js, I also noticed that there
were unused calls to %FunctionSetName and %SetNativeFlag (those
calls are already handled by InstallGetter()).
Review URL: https://codereview.chromium.org/1838563003
Cr-Commit-Position: refs/heads/master@{#35076}
This patch implements ES2015 RegExp subclassing semantics, namely the
hardest part where RegExp.prototype.exec and certain flag getters can
be overridden in order to provide different behavior. This change is
hidden behind a new flag, --harmony-regexp-exec. The flag guards the
behavior by installing entirely different implementations of the
methods which follow the new semantics.
Preliminary performance tests show a 3-4x regression in the Octane
RegExp benchmark. The new code doesn't call out into several fast
paths that the old code supported, so this is expected.
The patch is tested mostly by test262, where most RegExp tests are fixed,
with the exception of deliberate spec violations for web compatibility,
and for the 'sticky' flag, which is not dynamically read by this patch
in all cases but rather statically compiled into the RegExp. The latter
will require a follow-on patch to implement. A small additional set of
tests verifies one particular case, mostly to check whether the flag
mechanism works.
R=adamk,yangguo@chromium.org
LOG=Y
BUG=v8:4602
Review URL: https://codereview.chromium.org/1596483005
Cr-Commit-Position: refs/heads/master@{#35068}
Reason for revert:
Makes nosnap bots timeout due to having to rebuild bytecode handlers.
Original issue's description:
> [Interpreter] Remove separate Ignition snapshot.
>
> Removes the seperate Ignition snapshot and build the Ignition bytecode
> handlers in the default snapshot.
>
> BUG=v8:4280
> LOG=N
>
> Committed: https://crrev.com/1798f3fe84faff32ba44e09f6aed79245dd98d80
> Cr-Commit-Position: refs/heads/master@{#35058}
TBR=machenbach@google.com,yangguo@chromium.org,mstarzinger@chromium.org,machenbach@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4280
Review URL: https://codereview.chromium.org/1827143002
Cr-Commit-Position: refs/heads/master@{#35059}
Removes the seperate Ignition snapshot and build the Ignition bytecode
handlers in the default snapshot.
BUG=v8:4280
LOG=N
Review URL: https://codereview.chromium.org/1833643002
Cr-Commit-Position: refs/heads/master@{#35058}
The linter (i.e. cpplint.py) no longer needs to check for alpha-sorted
include directives because our source formatting (i.e. clang-format)
will take care of this by now. This is the current default configuration
of the underlying linter anyways.
Note that the two tools disagree about the correct ordering about files
containing dash characters. The ordering suggested by the formatter is
more natural. Having the formatter trigger linter errors is not a good
situation to be in.
R=jochen@chromium.org
Review URL: https://codereview.chromium.org/1822003002
Cr-Commit-Position: refs/heads/master@{#34985}
Introduces a bytecode whose handler executes the equivalent of %_IsArray and %_IsJSReceiver without a runtime call.
BUG=v8:4822
LOG=y
Review URL: https://codereview.chromium.org/1645763003
Cr-Commit-Position: refs/heads/master@{#34983}
Both of them shipped in Chrome 49 without incident.
Also move relevant tests from harmony/ to es6/.
Review URL: https://codereview.chromium.org/1815773002
Cr-Commit-Position: refs/heads/master@{#34964}
This change introduces wide prefix bytecodes to support wide (16-bit)
and extra-wide (32-bit) operands. It retires the previous
wide-bytecodes and reduces the number of operand types.
Operands are now either scalable or fixed size. Scalable operands
increase in width when a bytecode is prefixed with wide or extra-wide.
The bytecode handler table is extended to 256*3 entries. The
first 256 entries are used for bytecodes with 8-bit operands,
the second 256 entries are used for bytecodes with operands that
scale to 16-bits, and the third group of 256 entries are used for
bytecodes with operands that scale to 32-bits.
LOG=N
BUG=v8:4747,v8:4280
Review URL: https://codereview.chromium.org/1783483002
Cr-Commit-Position: refs/heads/master@{#34955}
Bounds check hoisting was known to be buggy and has never been turned on.
Since Crankshaft is deprecated, nobody is going to spend time fixing it,
so let's just get rid of it.
BUG=v8:4155,v8:4849
LOG=n
R=bmeurer@chromium.org
Review URL: https://codereview.chromium.org/1823623002
Cr-Commit-Position: refs/heads/master@{#34948}
(The goal is to have CodeStubAssembler be the sole assembler-like user of
the TF compiler pipeline; with RMA being a private implementation detail
and FAA being a client.)
BUG=chromium:508898
LOG=Y
Review URL: https://codereview.chromium.org/1674633002
Cr-Commit-Position: refs/heads/master@{#34852}
A startup snapshot is considered cold when it does not contain any
function code. We can now create a warm startup snapshot from a cold one
by running a warm-up script. Functions exercised by the warm-up script
are compiled and its code included in the warm startup snapshot. Side
effects caused by the warm-up script does not persist.
R=vogelheim@chromium.org
BUG=v8:4836
LOG=Y
Review URL: https://codereview.chromium.org/1805903002
Cr-Commit-Position: refs/heads/master@{#34849}
This will allow to only load json data for the files under
review instead of the whole data set.
This will be called on the infra-side after all coverage
data has been merged.
Also fix a bunch of log lines.
BUG=chromium:568949
LOG=n
NOTRY=true
Review URL: https://codereview.chromium.org/1808663002
Cr-Commit-Position: refs/heads/master@{#34834}
The feature was removed from the bots a while ago. It was
superseeded by the flaky-test detection which reruns tests.
Remaining tests still marked as flaky most certainly pass
since a while.
Referencing all the bugs whose expectations lines get
removed by this.
BUG=v8:3838,v8:3525,v8:3125
LOG=n
Review URL: https://codereview.chromium.org/1802983002
Cr-Commit-Position: refs/heads/master@{#34804}
Sometimes v8.log entries are cut off, and leave an unpaired quote.
Since the log is piped into d8 to run the tick processor, that quote
is interpreted to escape a line break.
This fix makes sure that we break lines even with unpaired quotes.
R=jkummerow@chromium.org
Review URL: https://codereview.chromium.org/1802303002
Cr-Commit-Position: refs/heads/master@{#34786}
test262 "negative" test expectations list which exception is thrown. The ES2017
draft specification is very specific about which exception class is thrown
from which path, and V8 works hard to be correct with respect to that spec.
Previously, the test262 test runner would accept any nonzero status code,
such as from a crash, or a FAIL printed out, for a negative test. This
patch makes negative tests check for the right answer using a quick-and-dirty
parsing of the exception printing from d8 to find the exception class.
It invokes d8 in a way to get a status code of 0 from thrown exceptions
so that 'negative' tests aren't actually implemented by negating the output.
Amazingly, this didn't catch any test262 failures, but I verified the extra
checking interactively by changing a negative test to expect a different type
and saw it fail.
BUG=v8:4803
R=machenbach
LOG=Y
Review URL: https://codereview.chromium.org/1766503002
Cr-Commit-Position: refs/heads/master@{#34763}
After histrogram timer added time recaling functionality,
some events, e.g. parse, histogram timer generates event log ending with 'MicroSeconds'.
Since ProfViz can't recorgnize it, this patch cuts off 'MicroSeconds' postfix.
R=vogelheim@chromium.org, yangguo@chromium.org
BUG=chromium:
LOG=N
Review URL: https://codereview.chromium.org/1771293002
Cr-Commit-Position: refs/heads/master@{#34710}
This also runs the message test suite against Ignition. By now most of
the source positions (and exception messages) are accurate, the failing
ones have been blacklisted.
R=machenbach@chromium.org
Review URL: https://codereview.chromium.org/1783773003
Cr-Commit-Position: refs/heads/master@{#34708}
This adds a function to the sancov_merger that merges the
output files of one swarming shard in parallel. This will
be called from the infrastructure when collecting/merging
swarming results.
The tool will be called subsequently for each shard. On
the first call, the target dir will be empty and the sancov
files will just be moved.
BUG=chromium:568949
LOG=n
NOTRY=true
Review URL: https://codereview.chromium.org/1782843002
Cr-Commit-Position: refs/heads/master@{#34678}
Changes include:
- better test coverage for builds with snapshot
- write snapshot blobs to buffer instead of test serialization files
- renamed tests
R=machenbach@chromium.org
Review URL: https://codereview.chromium.org/1777213002
Cr-Commit-Position: refs/heads/master@{#34657}
With this, the test runner automatically merges sancov
files after testing. There's no need to do this by some
external infrastructure.
In a future CL, we could even merge during testing to lift
harddisk pressure.
BUG=chromium:568949
LOG=n
NOTRY=true
Review URL: https://codereview.chromium.org/1776123002
Cr-Commit-Position: refs/heads/master@{#34606}
This adds sanitizer-coverage compilation, test-runner
features and post processing.
Sanitizer coverage is expected to be used together with
asan.
During test runner execution, the produced sancov files
are disambiguated and match the pattern:
<executable name>.test.<test id>.sancov.
Two additional scripts are added for merging raw sancov
files and for generating json data containing all
instrumented lines + all covered lines from merged sancov
files. Both scripts use multiprocessing for speed.
The json data will later be uploaded to google storage
for further use, e.g. to show coverage data in rietveld.
Sancov documentation:
http://clang.llvm.org/docs/SanitizerCoverage.html
BUG=chromium:568949
LOG=n
NOTRY=true
TEST=python -m unittest sancov_formatter_test
TEST=python -m unittest sancov_merger_test
Review URL: https://codereview.chromium.org/1737263003
Cr-Commit-Position: refs/heads/master@{#34578}
Introducing the KeyAccumulator accidentally removed some crucial fast-paths.
This CL starts rewriting the KeyAccumulator, step-by-step introducing the
special cases again.
BUG=chromium:545503, v8:4758
LOG=y
Review URL: https://codereview.chromium.org/1707743002
Cr-Commit-Position: refs/heads/master@{#34532}
The CompilationPhase helper class is only used in Crankshaft and is not
suitable for use in other compilers. This factors is out into a separate
file and moves it into the "crankshaft" directory.
R=jkummerow@chromium.org
Review URL: https://codereview.chromium.org/1758773002
Cr-Commit-Position: refs/heads/master@{#34441}
Initial implementation of S390 specific debug and IC functions.
R=danno@chromium.org,jkummerow@chromium.org,jochen@chromium.org,jyan@ca.ibm.com,michael_dawson@ca.ibm.com,mbrandy@us.ibm.com
BUG=
Review URL: https://codereview.chromium.org/1743263003
Cr-Commit-Position: refs/heads/master@{#34400}
Initial commit with the bulk of the src/s390/* changes
along with associated changes to the build toolchain for
the new files.
A minor update to V8PRIuPTR definition for Mac OS X
affecting 32-bit S390 sim compilations.
R=danno@chromium.org,jkummerow@chromium.org,jochen@chromium.org,jyan@ca.ibm.com,michael_dawson@ca.ibm.com,mbrandy@us.ibm.com
BUG=
Review URL: https://codereview.chromium.org/1725243004
Cr-Commit-Position: refs/heads/master@{#34331}
Adds support for cpu profiler logging to the interpreter. Modifies the
the API to be passed AbstractCode objects instead of Code objects, and
adds extra functions to AbstractCode which is required by log.cc and
cpu-profiler.cc.
The main change in sampler.cc is to determine if a stack frame is an
interpreter stack frame, and if so, use the bytecode address as the pc
for that frame. This allows sampling of bytecode functions. This
requires adding support to SafeStackIterator to determine if a frame is
interpreted, which we do by checking the PC against pre-stored addresses
for the start and end of interpreter entry builtins.
Also removes CodeDeleteEvents which are dead code and haven't
been reported for some time.
Still to do is tracking source positions which will be done in a
followup CL.
BUG=v8:4766
LOG=N
Review URL: https://codereview.chromium.org/1728593002
Cr-Commit-Position: refs/heads/master@{#34321}
This reverts commit 9146bc5e20.
This contains a fix for the following crash:
1. We record slots for a fixed array.
2. We trim the fixed array, so that some recorded slots are now in free space.
3. During mark-compact we sweep the page with the fixed array. Now free list items contain memory with recorded slots.
4. We evacuate a byte array using the new free list items.
5. We iterate slots that are now inside the byte array and crash.
BUG=chromium:589413,chromium:578883
LOG=NO
Review URL: https://codereview.chromium.org/1735523002
Cr-Commit-Position: refs/heads/master@{#34302}
Reason for revert:
Revert because of canary crashes: crbug.com/589413
Original issue's description:
> Replace slots buffer with remembered set.
>
> Slots pointing to evacuation candidates are now recorded in the new RememberedSet<OLD_TO_OLD>.
>
> The remembered set is extended to support typed slots.
>
> During parallel evacuation all migration slots are recorded in local slots buffers.
> After evacuation all local slots are added to the remembered set.
>
> BUG=chromium:578883
> LOG=NO
>
> Committed: https://crrev.com/2285a99ef6f7d52f4f0c4d88a7db4224443ee152
> Cr-Commit-Position: refs/heads/master@{#34212}
TBR=jochen@chromium.org,hpayer@chromium.org,mlippautz@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:578883
Review URL: https://codereview.chromium.org/1725073003
Cr-Commit-Position: refs/heads/master@{#34238}
