[Bindings] Create and use V8 context snapshots

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

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/SourceLocation.h"
 #include "bindings/core/v8/UseCounterCallback.h"
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "bindings/core/v8/V8DOMException.h"
 #include "bindings/core/v8/V8ErrorEvent.h"
 #include "bindings/core/v8/V8ErrorHandler.h"
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8IdleTaskRunner.h"
 #include "bindings/core/v8/V8Location.h"
+#include "bindings/core/v8/V8SnapshotCreator.h"
 #include "bindings/core/v8/V8Window.h"
 #include "bindings/core/v8/WorkerOrWorkletScriptController.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/inspector/MainThreadDebugger.h"
 #include "core/workers/WorkerGlobalScope.h"
@@ skipping 385 matching lines @@
 
     process_total += diff;
     DCHECK_GE(process_total, 0)
         << "total amount = " << process_total << ", diff = " << diff;
   }
 #endif
 
   v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(diff);
 }
 
-void V8Initializer::InitializeMainThread() {
+void V8Initializer::InitializeMainThread(intptr_t* table) {

[Yuki, 2017/05/12 15:20:10]

|table| doesn't make much sense.
v8_snapshot_external_references for example?

Should this be retrieved through V8SnapshotCreator::GetExternalReferences()
rather than passing in as an argument?

[peria, 2017/05/30 08:25:42]

Acknowledged.

   DCHECK(IsMainThread());
 
   WTF::ArrayBufferContents::Initialize(AdjustAmountOfExternalAllocatedMemory);
 
   DEFINE_STATIC_LOCAL(ArrayBufferAllocator, array_buffer_allocator, ());
   auto v8_extras_mode = RuntimeEnabledFeatures::experimentalV8ExtrasEnabled()
                             ? gin::IsolateHolder::kStableAndExperimentalV8Extras
                             : gin::IsolateHolder::kStableV8Extras;
   gin::IsolateHolder::Initialize(gin::IsolateHolder::kNonStrictMode,
                                  v8_extras_mode, &array_buffer_allocator);
 
   // NOTE: Some threads (namely utility threads) don't have a scheduler.
-  WebScheduler* scheduler = Platform::Current()->CurrentThread()->Scheduler();
+  WebThread* thread = Platform::Current()->CurrentThread();
+  WebScheduler* scheduler = thread ? thread->Scheduler() : nullptr;
+
   // When timer task runner is used for PerIsolateData, GC tasks are getting
   // throttled and memory usage goes up. For now we're using loading task queue
   // to prevent this.
   // TODO(altimin): Consider switching to timerTaskRunner here.
   v8::Isolate* isolate = V8PerIsolateData::Initialize(
       scheduler ? scheduler->LoadingTaskRunner()
-                : Platform::Current()->CurrentThread()->GetWebTaskRunner());
+                : thread ? thread->GetWebTaskRunner() : nullptr,
+      table, V8SnapshotCreator::TakingSnapshot());
 
   InitializeV8Common(isolate);
 
   isolate->SetOOMErrorHandler(ReportOOMErrorInMainThread);
   isolate->SetFatalErrorHandler(ReportFatalErrorInMainThread);
   isolate->AddMessageListenerWithErrorLevel(
       MessageHandlerInMainThread,
       v8::Isolate::kMessageError | v8::Isolate::kMessageWarning |
           v8::Isolate::kMessageInfo | v8::Isolate::kMessageDebug |
           v8::Isolate::kMessageLog);
@@ skipping 103 matching lines @@
           v8::Isolate::kMessageLog);
   isolate->SetFatalErrorHandler(ReportFatalErrorInWorker);
 
   uint32_t here;
   isolate->SetStackLimit(reinterpret_cast<uintptr_t>(&here) -
                          kWorkerMaxStackSize);
   isolate->SetPromiseRejectCallback(PromiseRejectHandlerInWorker);
 }
 
 }  // namespace blink