Use timer task runner for V8PerIsolate tasks

third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp b/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
index c27265962343a6e4872d4dc2960c5713b4662d37..099716ed80f665a3a7f31b6fd344846b6934e7e6 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
@@ -403,7 +403,9 @@ void V8Initializer::initializeMainThread() {
   gin::IsolateHolder::Initialize(gin::IsolateHolder::kNonStrictMode,
                                  v8ExtrasMode, &arrayBufferAllocator);
 
-  v8::Isolate* isolate = V8PerIsolateData::initialize();
+  WebScheduler* scheduler = Platform::current()->currentThread()->scheduler();
+  v8::Isolate* isolate =
+      V8PerIsolateData::initialize(scheduler->timerTaskRunner());

[Ken Rockot(use gerrit already), 2017/01/10 22:20:23]

I would be surprised if we aren't seeing crashes in the wild because of this CL.
There is an implementation of WebThread in use for content utility processes
which always has a null scheduler(). If we're seeing crashes, we should probably
revert and reland once this code can be changed or we add a scheduler impl to
WebThreadImplForUtilityThread.

 
   initializeV8Common(isolate);
 
@@ -420,7 +422,6 @@ void V8Initializer::initializeMainThread() {
       codeGenerationCheckCallbackInMainThread);
 
   if (RuntimeEnabledFeatures::v8IdleTasksEnabled()) {
-    WebScheduler* scheduler = Platform::current()->currentThread()->scheduler();
     V8PerIsolateData::enableIdleTasks(
         isolate, WTF::makeUnique<V8IdleTaskRunner>(scheduler));
   }