This was missed during a file move and can cause build bugs.
Bug: chromium:991547
Change-Id: I157e7bb656956c08293c205c0d00884aecc7adee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798430
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Auto-Submit: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63711}
Bug: v8:7790
Change-Id: I1abffc574b1d9964940625b1f15fc4d98f170b7b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798682
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63710}
This fixes the case where a table entry contains a function constructed
via {WebAssembly.Function} and is then read out via a runtime function
from the table.
R=ahaas@chromium.org
TEST=mjsunit/regress/wasm/regress-crbug-1002388
BUG=chromium:1002388
Change-Id: Ic0a9a544baaf37e68cd22eb91f2ef0bdf5fa5842
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795352
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63709}
Currently the dispatch table could be accessed out of bounds if something
is wrong with the generated bytecode.
OOB access of the dispatch table can lead to jumps to arbitrary addresses
in the code space.
This CL prevents this issue by changing the following:
BYTECODE_MASK now filters out all bits not currently used for bytecodes.
All unused slots between the last actually defined bytecode and
BYTECODE_MASK are now filled with BREAK Bytecodes (invalid operation).
This way we can not access out of bounds of the dispatch table if
something is broken/tampered with, preventing jumps to arbitrary code.
Bug: v8:9699
Change-Id: Ibce591ae94b52472ba74a9fd0666e55185af7b2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795349
Commit-Queue: Patrick Thier <pthier@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63708}
This reverts commit 4a16305b65.
Reason for revert: Need to revalidate assumptions behind the CHECK.
Original change's description:
> [compiler] Optionally apply an offset to stack checks
>
> The motivation behind this change is that the frame size of an optimized
> function and its unoptimized version may differ, and deoptimization
> may thus trigger a stack overflow. The solution implemented in this CL
> is to optionally apply an offset to the stack check s.t. the check
> becomes 'sp - offset > limit'. The offset is applied to stack checks at
> function-entry, and is set to the difference between the optimized and
> unoptimized frame size.
>
> A caveat: OSR may not be fully handled by this fix since we've already
> passed the function-entry stack check. A possible solution would be to
> *not* skip creation of function-entry stack checks for inlinees.
>
> This CL: 1. annotates stack check nodes with the stack check kind, where
> kind is one of {function-entry,iteration-body,unknown}. 2. potentially
> allocates a temporary register to store the result of the 'sp - offset'
> in instruction selection (and switches input registers to 'unique'
> mode). 3. Applies the offset in code generation.
>
> Drive-by: Add src/compiler/globals.h for compiler-specific globals.
>
> Bug: v8:9534,chromium:1000887
> Change-Id: I257191c4a4978ccb60cfa5805ef421f30f0e9826
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1762521
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63701}
TBR=neis@chromium.org,sigurds@chromium.org,jgruber@chromium.org
Change-Id: Iebf46d5256b6dee13451741781ef85a5fe9b1628
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9534, chromium:1000887
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1800565
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63706}
Current GetIterator bytecode loads and calls @@iterator property on a
given object. This change extends the bytecode functionality to check
whether the value returned after calling @@iterator property is a valid
JSReceiver. The bytecode throws SymbolIteratorInvalid exception if the
returned value is not a valid JSReceiver. This change absorbs the
functionality of additional two bytecodes - JumpIfJSReceiver and
CallRuntime, that are part of the iterator protocol in the GetIterator
bytecode.
Bug: v8:9489
Change-Id: I9e84cfe85eeb9a1b8a97ca0595375ac26ba1bbfd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1792905
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Swapnil Gaikwad <swapnilgaikwad@google.com>
Cr-Commit-Position: refs/heads/master@{#63704}
This removes the {base::ReversedAdapter} class and uses
{base::iterator_range} instead. The types are inferred from what
{std::rbegin} and {std::rend} return.
Since src/base/adapters.h would only contain this one method after
this refactoring, it was merged into src/base/iterator.h.
Some includes of src/base/adapters.h were unused and hence dropped.
R=mlippautz@chromium.org
Bug: v8:9396
Change-Id: I597172ec790193b73af196d1afcd64bbed0a597d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798432
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63703}
The motivation behind this change is that the frame size of an optimized
function and its unoptimized version may differ, and deoptimization
may thus trigger a stack overflow. The solution implemented in this CL
is to optionally apply an offset to the stack check s.t. the check
becomes 'sp - offset > limit'. The offset is applied to stack checks at
function-entry, and is set to the difference between the optimized and
unoptimized frame size.
A caveat: OSR may not be fully handled by this fix since we've already
passed the function-entry stack check. A possible solution would be to
*not* skip creation of function-entry stack checks for inlinees.
This CL: 1. annotates stack check nodes with the stack check kind, where
kind is one of {function-entry,iteration-body,unknown}. 2. potentially
allocates a temporary register to store the result of the 'sp - offset'
in instruction selection (and switches input registers to 'unique'
mode). 3. Applies the offset in code generation.
Drive-by: Add src/compiler/globals.h for compiler-specific globals.
Bug: v8:9534,chromium:1000887
Change-Id: I257191c4a4978ccb60cfa5805ef421f30f0e9826
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1762521
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63701}
This moves the code to allocate the far jump table from
{SetRuntimeStubs} to {AddCodeSpace} to allocate one such table per code
space.
Also, the {runtime_stub_table_} and {runtime_stub_entries_} fields do
not make sense any more now and are replaced by calls to
{GetNearRuntimeStubEntry} and {GetRuntimeStubId}.
R=mstarzinger@chromium.org
Bug: v8:9477
Change-Id: Ie1f5c9d4eb282270337a684c34f097d8077fdfbb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795348
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63700}
This reduces the runtime from ~20m to ~2m (very unscientific measure
based on running the entire asm-wasm-i32 test with and without this
change).
I removed most of the constants that looked uninteresting, e.g. testing
for 10, 20, 30, isn't that interesting. The edge cases are left
untouched, min/max signed positive/negative ints and +/- 1 from both.
Bug: v8:7783
Bug: v8:9396
Change-Id: Ice363fc3f786dd55ff118ffa42f9ecea07880338
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1791632
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63695}
This adds a new API function and provides a simple implementation
of performance.measureMemory() in d8. The implementation currently
immediately resolves the result promise with the current heap size.
Bug: chromium:973627
Change-Id: Ia8e1963a49b7df628b5487a2c0d601473f0cb039
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796502
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63694}
Implementations for other architectures will follow in subsequent
changes.
Bug: v8:8460
Change-Id: I279388ab76b1d88d65cbe179088be5573c17fc58
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796317
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63693}
This reverts commit 591d1c9de4.
Reason for revert: breaks blink
Original change's description:
> [top-level-await] Implement top-level-await in V8
>
> Implements AsyncModules in SourceTextModule. However, there is no
> support in the parser or D8 for actually creating / resolving
> AsyncModules. Also adds a flag '--top-level-await,' but the only
> external facing change with the flag enabled is that Module::Evaluate
> returns a promise.
>
> Bug: v8:9344
> Change-Id: Idc722efc1e2aa780d04bdb985bb7920ab969d34e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1728037
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Commit-Queue: Joshua Litt <joshualitt@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63686}
TBR=ulan@chromium.org,adamk@chromium.org,neis@chromium.org,joshualitt@chromium.org
Change-Id: I6ceeb3a293a948af04bf200ab784ceb03386a3fd
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9344
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1797656
Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63692}
This speeds up the check by ~10x.
This was tested by writing a simple test that compares a for-loop and
array.every():
for (var i = 0; i < kMemSize; i++) {
assertEquals(0, array[i]);
}
assertTrue(array.every((e => e == 0)));
The for-loop takes ~180s, every() takes ~19s.
Numbers above are for arm.debug build (simulator). On x64.debug builds
we can see a similar 10x improvement, from ~6s to ~400ms.
Bug: v8:7783
Bug: v8:9396
Change-Id: I83d46c7ec4a634612032c1d79585339cadb8b641
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1793904
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63691}
This is a first step towards removal of dynamic ParameterMode.
Bug: v8:9708
Change-Id: I3502584264952dc12b44fd85b91274c9a0ddf31d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798622
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63688}
Ensure that the jump tables do not take more than 50% of newly reserved
code spaces. In particular, this ensures that the jump tables always
fit in the newly reserved code space.
R=mstarzinger@chromium.org
Bug: v8:9477
Change-Id: I72cdbb7c7dc7916167594c0fc8e1ddb1511756ff
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1782559
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63687}
Implements AsyncModules in SourceTextModule. However, there is no
support in the parser or D8 for actually creating / resolving
AsyncModules. Also adds a flag '--top-level-await,' but the only
external facing change with the flag enabled is that Module::Evaluate
returns a promise.
Bug: v8:9344
Change-Id: Idc722efc1e2aa780d04bdb985bb7920ab969d34e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1728037
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Joshua Litt <joshualitt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63686}
SharedFunctionInfos that do not belong to a script were tracked in
noscript_shared_function_infos. However this was only used in object-stats.
Remove this since it was actually leaking memory in some use cases.
Bug: v8:9674
Change-Id: I9482f7e5dedf975666a70684b3d2ea04c9a23518
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798423
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63685}
This is a reland of d7d25d2abc
Original change's description:
> [wasm] Patch jump tables in all code spaces
>
> If there are multiple code spaces, make sure to patch the jump tables
> in all of them.
>
> R=mstarzinger@chromium.org
>
> Bug: v8:9477
> Change-Id: I2ec3d3de913b99623fd310004555337329588da0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1789289
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63651}
Bug: v8:9477
Change-Id: I89c3d59d8366ac9479e58feea91dd40ee4e01f66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796065
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63683}
The jump table assembler is implemented on all architectures now, so
remove the default code. It would be untested otherwise.
R=mstarzinger@chromium.org
Change-Id: I45e42fc04ebb3bb07d975648b1498e2ea4e757d4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796328
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63682}
... to precisely express which guarantees does this operator provide.
Drive-by-fix: use it for other tag-checking predicates in CSA.
Bug: v8:9396
Change-Id: Ifee22922ac02ec8866038be1a97625a32638d521
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795504
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63681}
This adds the --wasm-far-jump-table flag, which enables the extension
of the far jump table with a slot for each wasm function.
R=mstarzinger@chromium.org
Bug: v8:9477
Change-Id: I61cb4592aa8ed75e2772371e9b7dbfdfe9bb0046
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1792907
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63680}
This CL renames the runtime stub table to far jump table, and changes
the implementation so it can later be patched concurrently.
A follow-up CL will extend this table to also contain slots for wasm
functions (if needed).
R=mstarzinger@chromium.org
Bug: v8:9477
Change-Id: I20bf0a0bb66dc0333f794761c1506b27137b53e7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1789159
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63679}
Change-Id: Ie0bd818c629bed3011212fb7c8ab81202a462501
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798424
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63678}
This patch uses a bit in the Variable bit fields to distinguish
static private names from instance private names, so that we
can check the conflicts of private accessors that are complementary
but with different staticness in the parser, and use this
information later when generating code for checking static brands
for private method access.
Design doc: https://docs.google.com/document/d/1rgGRw5RdzaRrM-GrIMhsn-DLULtADV2dmIdh_iIZxlc/edit
Bug: v8:8330
Change-Id: I8d70600e594e3d07f77ea519751b7ca2e0de87b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1781010
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/master@{#63677}
Also converts ACP from a Cell to a PropertyCell.
Bug: v8:9463
Change-Id: I6cd26d4e4fd8869a17bf75f83cc177524f8082d7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795742
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Joshua Litt <joshualitt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63675}
... to make it "smi-corrupting" decompression-friendly.
Also add a cctest for the CSA implementation.
Bug: v8:9706
Change-Id: I1f1b0aa1b40832a0c2ce81658da316b3e442189c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796802
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63674}
Do not assume that the MaybeHandle that is returned when fetching for a property
is valid and instead check for its contents. Treat an empty handle as not
finding the right property.
Bug: chromium:1002827
Change-Id: Iac158086ec5f66cd9602f4a73ae78de367dd3e77
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796556
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63672}
This CL adds a test where we evaluate a variable that is context
allocated (through the use of 'eval'), but not used by the closure.
This did not work with the previous whitelist approach, but works now
with the new blacklist approach (see https://crrev.com/c/1795354)
Bug: v8:9482
Change-Id: I1e453dec0b624bf7e0312100e119d86c9c481ba9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796543
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63671}
From verwaest@ work on the Json's parser, we know that removing the allocation type argument when creating objects using the factory class increases performance. This will also allow us to optimise these functions in a latter CL.
Change-Id: If78f62a63fe41453f4def8bea77b6eddc2ab7f36
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1792168
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@google.com>
Cr-Commit-Position: refs/heads/master@{#63670}
functionality is:
If rhs_is_smi is true, we are sure that rhs is a Smi.
If rhs_is_smi is false, rhs might or not be a Smi.
Therefore, rhs_known_smi fits better.
Change-Id: Ie6dd0446ef85ba0730189e2012a21c24d1731b74
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1796551
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63669}
This CL changes how variables are resolved during debug evaluate.
We now re-parse the whole script when creating a ScopeIterator.
This gives us accurate scope information for all parent scopes of the
closure in which we stopped. Using this information, we build
blacklists of stack-allocated variables. Each context on the chain
in between the closure context up to the original native context is
wrapped in a debug-evaluate context with such a blacklist attached.
Variable lookup for debug-evalute contexts then works as follows:
1) Look up in the materialized stack variables (stayed the same).
2) Check the blacklist to find out whether to abort further lookup.
3) Look up in the original context.
Steps 1-3 is repeated for each debug-evaluate context, since they
mirror the original context chain.
R=ulan@chromium.org, yangguo@chromium.org
Change-Id: Ied8e5786772c70566da9627ee3b7eff066fba2b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795354
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63666}
Fix build errors introduced by
commit af063685fe
and not fully fixed by
commit db3cc4a247
Change-Id: Ifdc92f5d55061670127999058d374914985df762
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795643
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Mu Tao <pamilty@gmail.com>
Auto-Submit: Mu Tao <pamilty@gmail.com>
Cr-Commit-Position: refs/heads/master@{#63665}
Port ab0f971091
Original Commit Message:
- Eliminates non-const reference parameters in test/cctest.
Change-Id: I038314e0cc2b28e70e7ebcbd2d076ef62893285e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795646
Commit-Queue: Mu Tao <pamilty@gmail.com>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Auto-Submit: Mu Tao <pamilty@gmail.com>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63664}
