[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 22 matching lines @@
 #include "bindings/core/v8/ScriptController.h"
 #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/V8SnapshotUtil.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/csp/ContentSecurityPolicy.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/inspector/MainThreadDebugger.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "platform/EventDispatchForbiddenScope.h"
 #include "platform/RuntimeEnabledFeatures.h"
@@ skipping 320 matching lines @@
   V8PerIsolateData::From(isolate)->SetScriptWrappableVisitor(
       std::move(visitor));
   isolate->SetEmbedderHeapTracer(
       V8PerIsolateData::From(isolate)->GetScriptWrappableVisitor());
 
   isolate->SetMicrotasksPolicy(v8::MicrotasksPolicy::kScoped);
 
   isolate->SetUseCounterCallback(&UseCounterCallback);
   isolate->SetWasmModuleCallback(WasmModuleOverride);
   isolate->SetWasmInstanceCallback(WasmInstanceOverride);
+
+  v8::HandleScope handle_scope(isolate);
+  V8SnapshotUtil::EnsureInterfaceTemplates(isolate);
 }
 
 namespace {
 
 class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
   // Allocate() methods return null to signal allocation failure to V8, which
   // should respond by throwing a RangeError, per
   // http://www.ecma-international.org/ecma-262/6.0/#sec-createbytedatablock.
   void* Allocate(size_t size) override {
     return WTF::ArrayBufferContents::AllocateMemoryOrNull(
@@ skipping 34 matching lines @@
   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();
+  Platform* platform = Platform::Current();
+  WebThread* thread = platform->CurrentThread();
+  WebScheduler* scheduler = thread ? thread->Scheduler() : nullptr;

[Yuki, 2017/06/20 14:20:11]

Why |thread| can be null?

[peria, 2017/06/21 07:19:16]

In taking snapshot process, we have no implementation for
Platform::CurrentThread(), and it returns 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,
+      V8SnapshotUtil::GetReferenceTable(),
+      platform->IsToTakeV8Snapshot()
+          ? V8PerIsolateData::V8ContextMode::kTakeSnapshot
+          : V8PerIsolateData::V8ContextMode::kUseSnapshot);
 
   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