If the imported wasm function is being debugged (i.e. redirects to the
interpreter), call it via the JS_TO_WASM stub, such that we can disable
the breakpoint later by patching the exported function.
This also contains a drive-by fix in wasm-translation.cc (for the case
that all known positions are bigger than the requested one).
R=titzer@chromium.org, kozyatinskiy@chromium.org
BUG=v8:5971, v8:5822
Review-Url: https://codereview.chromium.org/2720813002
Cr-Commit-Position: refs/heads/master@{#43583}
With inline breakpoints DevTools are ready for break position aligned breakpoints instead of statement aligned.
BUG=chromium:695236
R=dgozman@chromium.org,yangguo@chromium.org
Review-Url: https://codereview.chromium.org/2709263002
Cr-Commit-Position: refs/heads/master@{#43385}
In current implementation we don't support nested scheduled break at all. If one break was scheduled inside another and second one doesn't produce actual break (execution was in blackboxed code or no JavaScript was executed) then second one will clear first scheduled break even if any not blackboxed JavaScript will be executed later.
Ambiguous break reason is added for the case when we have more then one scheduled reason. "auxData" in this case contains object with array of { reason: reason, auxData: auxData } objects for each reason in 'reasons' property.
BUG=chromium:632405
Review-Url: https://codereview.chromium.org/2678313002
Cr-Commit-Position: refs/heads/master@{#43021}
- removed getGeneratorObjectLocation from debugger-script.js,
- one more step to remove all debugger context usages in inspector.
BUG=v8:5510
R=yangguo@chromium.org,jgruber@chromium.org,alph@chromium.org
Review-Url: https://codereview.chromium.org/2678143002
Cr-Commit-Position: refs/heads/master@{#43018}
- entries preview available even if debugger agent is disabled,
- less deprecated mirrors usage in debugger-script.js
- no usage of debugger context - zero probability of leaking it.
- better test coverage.
BUG=v8:5510
R=yangguo@chromium.org,jgruber@chromium.org,alph@chromium.org,luoe@chromium.org
Review-Url: https://codereview.chromium.org/2672213002
Cr-Commit-Position: refs/heads/master@{#42978}
Blink uses access checks to be sure that objects from one context doesn't access objects in another. Heap profiler uses current context to call this checks, we need to be sure that current context is empty to allow heap profiler collect all objects without crash.
BUG=chromium:661223
R=alph@chromium.org,ulan@chromium.org
Review-Url: https://codereview.chromium.org/2669393002
Cr-Commit-Position: refs/heads/master@{#42939}
V8DebuggerAgentImpl::m_skipAllPaused is moved to V8Debugger.
V8DebuggerAgentImpl::didPaused doesn't return shouldBreak flag and called only when break is required and stack trace presented.
V8DebuggerAgentImpl doesn't store paused context.
Logic of conversion step-next at return into step-in is moved to debug.cc.
BUG=none
R=dgozman@chromium.org,yangguo@chromium.org
Review-Url: https://codereview.chromium.org/2668763003
Cr-Commit-Position: refs/heads/master@{#42907}
Without this CL we have only limit for amount of console messages and if user are dumping a huge messages we pretty soon run out of memory.
So let's introduce limit for memory consumption it would help chromium and Node.js as well.
BUG=chromium:671489
R=dgozman@chomium.org,alph@chromium.org, hpayer@chromium.org, ulan@chromium.org
Review-Url: https://codereview.chromium.org/2653293003
Cr-Commit-Position: refs/heads/master@{#42780}
Always execute the implicit return if we fell off the function bytes.
This is not considered an additional "step" as it is not executing a
wasm instruction.
Otherwise, we might pause at an invalid position (one after the
function bytes).
R=titzer@chromium.org
BUG=v8:5822
Review-Url: https://codereview.chromium.org/2650293003
Cr-Commit-Position: refs/heads/master@{#42730}
This CL adds --crankshaft and --no-always-opt flags to the tests that use
assertOptimized() and assertUnoptimized() respectively.
This CL also adds presubmit checks that ensure that tests have the proper
flags set.
BUG=v8:5890
Review-Url: https://codereview.chromium.org/2653753007
Cr-Commit-Position: refs/heads/master@{#42709}
With creation frame we can show additional information with description of each async stack trace, which could help user to understand where promises were chained.
At least in case of Promise.resolve().then(foo1).then(foo2) we would be able to show following stack trace for break in foo2 callback:
foo2 (test.js:14:2)
-- Promise.resolve (test.js:29:14)--
-- Promise.resolve (test.js:28:14)--
promiseThen (test.js:30:2)
More details: https://docs.google.com/document/d/1u19N45f1gSF7M39mGsycJEK3IPyJgIXCBnWyiPeuJFE
BUG=v8:5738
R=dgozman@chromium.org,gsathya@chromium.org
Review-Url: https://codereview.chromium.org/2648873002
Cr-Commit-Position: refs/heads/master@{#42682}
- kDebugPromiseCreated(task, parent_task)
This event occurs when promise is created (PromiseHookType::Init). V8Debugger uses this event to maintain task -> parent task map.
- kDebugEnqueueAsyncFunction(task)
This event occurs when first internal promise for async function is created. V8Debugger collects stack trace at this point.
- kDebugEnqueuePromiseResolve(task),
This event occurs when Promise fulfills with resolved status. V8Debugger collects stack trace at this point.
- kDebugEnqueuePromiseReject(task),
This event occurs when Promise fulfills with rejected status. V8Debugger collects stack trace at this point.
- kDebugPromiseCollected,
This event occurs when Promise is collected and no other chained callbacks can be added. V8Debugger removes information about async task for this promise.
- kDebugWillHandle,
This event occurs when chained promise function (either resolve or reject handler) is called. V8Debugger installs parent promise's stack (based on task -> parent_task map) as current if available or current promise's scheduled stack otherwise.
- kDebugDidHandle,
This event occurs after chained promise function has finished. V8Debugger restores asynchronous call chain to previous one.
With this change all instrumentation calls are related to current promise (before WillHandle and DidHandle were related to next async task).
Before V8Debugger supported only the following:
- asyncTaskScheduled(task1)
- asyncTaskStarted(task1)
- asyncTaskFinished(task1)
Now V8Debugger supports the following:
- asyncTaskScheduled(parent_task)
..
- asyncTaskCreated(task, parent_task),
- asyncTaskStarted(task), uses parent_task scheduled stack
- asyncTaskScheduled(task)
- asyncTaskFinished(task)
Additionally: WillHandle and DidHandle were migrated to PromiseHook API.
More details: https://docs.google.com/document/d/1u19N45f1gSF7M39mGsycJEK3IPyJgIXCBnWyiPeuJFE
BUG=v8:5738
R=dgozman@chromium.org,gsathya@chromium.org,yangguo@chromium.org
Review-Url: https://codereview.chromium.org/2650803003
Cr-Commit-Position: refs/heads/master@{#42644}
V8 has internal mechanism to ignore steps and breaks inside internal scripts, in this CL it's reused for blackboxing implementation.
Advantages:
- much faster blackboxing implementation (before we at least wrap and collect current call stack for each step),
- get rid of StepFrame action and potential pause in blackboxed code after N StepFrame steps,
- simplification of debugger agent logic.
Disadvtanges:
- currently when user was paused in blackboxed code (e.g. on breakpoint) and then makes step action, debugger ignores blackboxed state of the script and allows to use step actions as usual - this behavior is regressed, we still able to support it on frontend side.
Current state and proposed changes for blackboxing: https://docs.google.com/document/d/1hnzaXPAN8_QC5ENxIgxgMNDbXLraM_OXT73rAyijTF8/edit?usp=sharing
BUG=v8:5842
R=yangguo@chromium.org,dgozman@chromium.org,alph@chromium.org
Review-Url: https://codereview.chromium.org/2633803002
Cr-Commit-Position: refs/heads/master@{#42614}
Currently V8 context just crashes on OOM, with this CL backend will send paused notification with OOM reason before OOM and will increase heap limits to allow further debugging on pause.
BUG=chromium:675911
Review-Url: https://codereview.chromium.org/2624543004
Cr-Commit-Position: refs/heads/master@{#42480}
V8InspectorSession::schedulePauseOnNextStatement and V8InspectorSession::cancelPauseOnNextStatement are now exposed in inspector tests. These methods are required at least for better blackboxing tests.
BUG=v8:5842
R=dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2636613002
Cr-Commit-Position: refs/heads/master@{#42469}
Reason for revert:
OK, the failure really does seem to be due to this patch: It triggers Clang to crash
FAILED: obj/test/unittests/unittests/function-body-decoder-unittest.obj
E:\b\build\slave\cache\cipd\goma/gomacc.exe ../../third_party/llvm-build/Release+Asserts/bin/clang-cl.exe /nologo /showIncludes /FC @obj/test/unittests/unittests/function-body-decoder-unittest.obj.rsp /c ../../test/unittests/wasm/function-body-decoder-unittest.cc /Foobj/test/unittests/unittests/function-body-decoder-unittest.obj /Fd"obj/test/unittests/unittests_cc.pdb"
Assertion failed: (NumGaps == 0 || Bias < MaxDefRange) && "large ranges should not have gaps", file E:\b\build\slave\win_upload_clang\build\src\third_party\llvm\lib\MC\MCCodeView.cpp, line 531
Wrote crash dump file "C:\Users\CHROME~2\AppData\Local\Temp\goma_temp.5068\clang-cl.exe-563144.dmp"
Let's leave it out for now.
Original issue's description:
> Reland of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #1 id:1 of https://codereview.chromium.org/2628883006/ )
>
> Reason for revert:
> Try a reland; this might not have been the source of tree-closing.
>
> Original issue's description:
> > Revert of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #3 id:40001 of https://codereview.chromium.org/2630553002/ )
> >
> > Reason for revert:
> > Caused tree to close by failing compilation:
> >
> > https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20clang/builds/4451
> >
> > Original issue's description:
> > > [wasm] Enforce that function bodies end with the \"end\" opcode.
> > >
> > > R=rossberg@chromium.org
> > > BUG=chromium:575167
> > >
> > > Review-Url: https://codereview.chromium.org/2630553002
> > > Cr-Commit-Position: refs/heads/master@{#42286}
> > > Committed: fcc6e85ec6
> >
> > TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=chromium:575167
> >
> > Review-Url: https://codereview.chromium.org/2628883006
> > Cr-Commit-Position: refs/heads/master@{#42287}
> > Committed: 1d32a3989b
>
> TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=chromium:575167
>
> Review-Url: https://codereview.chromium.org/2628203003
> Cr-Commit-Position: refs/heads/master@{#42296}
> Committed: e539bd8e0eTBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:575167
Review-Url: https://codereview.chromium.org/2633583002
Cr-Commit-Position: refs/heads/master@{#42298}
Reason for revert:
Try a reland; this might not have been the source of tree-closing.
Original issue's description:
> Revert of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #3 id:40001 of https://codereview.chromium.org/2630553002/ )
>
> Reason for revert:
> Caused tree to close by failing compilation:
>
> https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20clang/builds/4451
>
> Original issue's description:
> > [wasm] Enforce that function bodies end with the \"end\" opcode.
> >
> > R=rossberg@chromium.org
> > BUG=chromium:575167
> >
> > Review-Url: https://codereview.chromium.org/2630553002
> > Cr-Commit-Position: refs/heads/master@{#42286}
> > Committed: fcc6e85ec6
>
> TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=chromium:575167
>
> Review-Url: https://codereview.chromium.org/2628883006
> Cr-Commit-Position: refs/heads/master@{#42287}
> Committed: 1d32a3989bTBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:575167
Review-Url: https://codereview.chromium.org/2628203003
Cr-Commit-Position: refs/heads/master@{#42296}
... which were done after the promise has been resolved.
Goal of this CL - change promise instrumentation to support better callbacks, chained after promise resolution and prepare instrumentation for adding new asyncTaskCreated instrumentation.
Instrumentation changes:
- asyncTaskScheduled(recurring) when promise is fulfilled or rejected,
- asyncTaskCancelled when promise is collected (since [1] we can be sure that promise will survive scheduled microtasks).
Minor changes:
- async task type in inspector <-> debugger API transferred by enum instead of string,
- Debug manages async task ids based on promise objects.
More details: https://docs.google.com/document/d/1u19N45f1gSF7M39mGsycJEK3IPyJgIXCBnWyiPeuJFE
[1] https://codereview.chromium.org/2581503003/
BUG=chromium:632829,v8:5738
R=dgozman@chromium.org,yangguo@chromium.org,gsathya@chromium.org
Review-Url: https://codereview.chromium.org/2578923002
Cr-Commit-Position: refs/heads/master@{#42178}
This is more renaming work to comply with the naming in the public
design repository. E.g. types are called "value types" and we no longer
refer to ASTs.
R=clemensh@chromium.org
BUG=
Review-Url: https://codereview.chromium.org/2594993002
Cr-Commit-Position: refs/heads/master@{#41891}
Due to the isOwn check, functions inherited through prototype will not be
included in a preview.
BUG=645053
Review-Url: https://codereview.chromium.org/2554623003
Cr-Commit-Position: refs/heads/master@{#41566}
Getter properties are not currently included in the protocol's
Runtime.ObjectPreview. DevTools currently shows getter properties
when evaluating arrays in the console, and this CL brings them into
the preview generated for RemoteObjects.
Corresponding DevTools CL: https://codereview.chromium.org/2521513006/
BUG=666882
Review-Url: https://codereview.chromium.org/2508423002
Cr-Commit-Position: refs/heads/master@{#41565}
*and* report all "virtual" wasm scripts right when the wasm script is
registered at the inspector.
WasmScript is a subtype of Script, with the cast checking that it is
actually a wasm script.
This layout makes it quite easy to implement functionality that is only
available for wasm scripts, and allows to later directly use the
WasmCompiledModule instead of the i::Script for backing the
debug::WasmScript. We might also add virtual methods to
provide different implementations for GetSourcePosition, Source and
others.
DisassembleWasmFunction now also becomes a method of this class instead
of a static function on the DebugInterface.
The WasmTranslation now uses the new WasmScript type instead of the
Script wrapper, and also registers all virtual wasm scripts immediately
when the wasm script is made public to the inspector (when the wasm
module is created).
R=yangguo@chromium.org,dgozman@chromium.org,titzer@chromium.org
BUG=chromium:613110,chromium:659715
Review-Url: https://codereview.chromium.org/2531163010
Cr-Commit-Position: refs/heads/master@{#41519}
If we just call CreateDebugInfo in GetPossibleBreakpoints then we won't call PrepareFunctionForBreakPoints and won't be able to step into this function or pause at breakpoint inside.
BUG=v8:5695
R=dgozman@chromium.org,yangguo@chromium.org
Review-Url: https://codereview.chromium.org/2540943002
Cr-Commit-Position: refs/heads/master@{#41401}
This exposes scopes for suspended generator objects by adding a
[[Scopes]] internal property to generator objects, similar to how
scopes for functions currently not on the stack are handled.
BUG=chromium:667286
Review-Url: https://codereview.chromium.org/2516973003
Cr-Commit-Position: refs/heads/master@{#41244}
Descriptions for (typed)arrays will use parenthesis instead of square brackets
"Array(10)" instead of "Array[10]". This CL also adds size hints to descriptions
of maps and sets.
Related CL for DevTools: https://codereview.chromium.org/2524913002/
BUG=405845
Review-Url: https://codereview.chromium.org/2521853003
Cr-Commit-Position: refs/heads/master@{#41237}
When disassembling functions for the inspector, we used an internal
text representation before. This CL implements the official text
format like it is understood by the spec interpreter.
Example output:
func $main (param i32) (result i32)
block i32
get_local 0
i32.const 2
i32.lt_u
if
i32.const -2
return
end
get_local 0
call_indirect 0
end
R=rossberg@chromium.org, titzer@chromium.org
BUG=chromium:659715
Review-Url: https://codereview.chromium.org/2520943002
Cr-Commit-Position: refs/heads/master@{#41172}
Instead of directly using v8_enable_inspector_override from
build_overrides/v8.gni in all the GN configs, set a v8_enable_inspector
variable based on v8_enable_inspector_override and use that everywhere.
This is the more common pattern seen in over projects, and reduces the
need to include //build_overrides/v8.gni in many files.
Review-Url: https://codereview.chromium.org/2520683002
Cr-Commit-Position: refs/heads/master@{#41156}
With this change, WebAssembly.Memory objects have backing stores allocated as an
8GB region where everything beyond the size of the Wasm heap is inaccessible.
GrowMemory is now implemented by changing the protection on the guard regions to
make the new portions of the heap accessible.
Guard pages are not enabled by default, but this change adds a flag and a test
variant to make sure we get test coverage on them.
BUG= https://bugs.chromium.org/p/v8/issues/detail?id=5277
Review-Url: https://codereview.chromium.org/2396433008
Cr-Commit-Position: refs/heads/master@{#41089}
Inspector uses this type for all internal scripts, e.g. injected-script-source.js. Scripts with new type are not reported by remote debugging protocol, frames from them are ignored.
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
BUG=none
R=yangguo@chromium.org,dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2499273003
Cr-Commit-Position: refs/heads/master@{#41056}
Before, we allocated one script per function per instance, and each
script referenced the wasm instance and the function index. Now we only
allocate one script per compiled wasm module, so the script also only
references this WasmCompiledModule, which causes changes to many interfaces.
Instead of fixing the disassemble API only used via debug.js, I decided
to drop it for now. Some later CL will reintroduce it via
DebugInterface.
BUG=v8:5530,chromium:659715
R=yangguo@chromium.org, titzer@chromium.orgCC=jgruber@chromium.org
Review-Url: https://codereview.chromium.org/2493823003
Cr-Commit-Position: refs/heads/master@{#41004}
We are removing use of the debugger context. When the debugger triggers
compilation, we may not have a context from which to create a JSArray.
R=ishell@chromium.org
BUG=chromium:664577
Review-Url: https://codereview.chromium.org/2479123002
Cr-Commit-Position: refs/heads/master@{#40956}
We are removing use of the debugger context. When the debugger triggers
compilation, we may not have a context from which to create a JSArray.
R=ishell@chromium.org
Review-Url: https://codereview.chromium.org/2479123002
Cr-Commit-Position: refs/heads/master@{#40884}
This adds information about an exception's caught/uncaught status to the
Runtime.paused event in the data parameter:
{
"method": "Debugger.paused",
"params": {
"callFrames": [
[...]
],
"data": {
"description": "666",
"type": "number",
"uncaught": true, <---
"value": 666
},
"hitBreakpoints": [],
"reason": "exception"
}
}
BUG=v8:5530
Review-Url: https://codereview.chromium.org/2488733003
Cr-Commit-Position: refs/heads/master@{#40875}
Currently function like "() => 239" contains offset 3 as begin of function and 8 as end of function.
This CL changes this to 6 and 9 respectively.
BUG=chromium:566801
R=yangguo@chromium.org,dgozman@chromium.org
TBR=adamk@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
Review-Url: https://codereview.chromium.org/2488493003
Cr-Commit-Position: refs/heads/master@{#40864}
This method iterates through all shared function info which are related to passed script, compiles debug code for SFI in range if needed and returns possible break locations.
BUG=chromium:566801
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
Review-Url: https://codereview.chromium.org/2465553003
Cr-Commit-Position: refs/heads/master@{#40783}
In the asm.js to wasm pipeline, we generate an entry function with
BUILTIN code, but still attached to a TYPE_NORMAL script.
This fix avoids trying to set a breakpoint there, resulting in a crash
on DCHECK(shared->HasDebugInfo()).
Also add two inspector tests to track regressions.
BUG=v8:5568
R=titzer@chromium.org,mstarzinger@chromium.org
Review-Url: https://codereview.chromium.org/2457433002
Cr-Commit-Position: refs/heads/master@{#40633}
To achieve this:
- fixed crash on windows - String16::fromInteger used "%zu" which doesn't support by VS2013 compiler, wrapped with ifdef else.
- fixed asan for d8 - unique_ptr on array has single element type.
- force Debugger.disable at the end of test.
BUG=chromium:635948
R=dgozman@chromium.org,yangguo@chromium.org,machenbach@chromium.org
Review-Url: https://codereview.chromium.org/2450653002
Cr-Commit-Position: refs/heads/master@{#40546}
* introduced v8::DebugInterface::ChangeBreakOnException(Isolate*,ExceptionBreakState);
* migrated inspector to new API;
* added cctest for new API;
* added inspector test for setPauseOnExceptionState.
BUG=chromium:652939,v8:5510
R=dgozman@chromium.org,yangguo@chromium.org
Review-Url: https://chromiumcodereview.appspot.com/2396193002
Cr-Commit-Position: refs/heads/master@{#40413}
* Inspector should depend on v8_libbase, v8 depedency is added in conditions section.
* Inlined sources since they aren't used outside of this gyp file.
BUG=chromium:635948
R=dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2408833002
Cr-Commit-Position: refs/heads/master@{#40139}
String16 is not public part of src/inspector. All usage are replaced with vector of char/unit16_t to avoid potential linker problems.
BUG=chromium:635948
R=dgozman@chromium.org,machenbach@chromium.org
Review-Url: https://codereview.chromium.org/2403493002
Cr-Commit-Position: refs/heads/master@{#40098}
v8::Integer::Value() method returns int64 but all scriptIds are 32 bit based. We can safely cast int64 into int here to make compilers happy.
R=dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2394973002
Cr-Commit-Position: refs/heads/master@{#40016}
Added a test that Runtime.getProperties doesn't truncate Set and Map properties in [[Entries]] in internalProperties.
BUG=chromium:650729
R=dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2376863002
Cr-Commit-Position: refs/heads/master@{#39940}
- added inspector test suite definition in testcfg.py
- added JS infrastructure for tests in protocol-test.js
BUG=chromium:635948
R=dgozman@chromium.org,alph@chromium.org
Review-Url: https://codereview.chromium.org/2370743003
Cr-Commit-Position: refs/heads/master@{#39895}
- added test runner, that takes file names and V8 flags as arguments and run scripts from passed files with passed flags in frontend context
BUG=chromium:635948
R=dgozman@chromium.org,alph@chromium.org
Review-Url: https://codereview.chromium.org/2372793002
Cr-Commit-Position: refs/heads/master@{#39891}
- added the channel implementation,
- added inspector implementation,
- added v8::Extension for communication between backend and frontend.
BUG=chromium:635948
R=dgozman@chromium.org,alph@chromium.org
Review-Url: https://codereview.chromium.org/2368393003
Cr-Commit-Position: refs/heads/master@{#39888}
- added a inspector folder,
- added related GN and gyp files,
- added task handling infrastructure for test runner.
BUG=chromium:635948
R=dgozman@chromium.org,alph@chromium.org
Review-Url: https://codereview.chromium.org/2361623006
Cr-Commit-Position: refs/heads/master@{#39866}
