[Bindings] Create and use V8 context snapshots

third_party/WebKit/Source/web/WebKit.cpp

Index: third_party/WebKit/Source/web/WebKit.cpp
diff --git a/third_party/WebKit/Source/web/WebKit.cpp b/third_party/WebKit/Source/web/WebKit.cpp
index 1f5cc5b763a83c1d65413d616a256507b72fa8f7..4d7cd619e2225668a859930c51295cb00e1bdb2d 100644
--- a/third_party/WebKit/Source/web/WebKit.cpp
+++ b/third_party/WebKit/Source/web/WebKit.cpp
@@ -35,6 +35,8 @@
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8Initializer.h"
+#include "bindings/core/v8/V8SnapshotCreator.h"
+#include "bindings/modules/v8/V8SnapshotExternalReferences.h"
 #include "core/animation/AnimationClock.h"
 #include "core/layout/LayoutTheme.h"
 #include "core/page/Page.h"
@@ -81,7 +83,10 @@ static ModulesInitializer& GetModulesInitializer() {
 void Initialize(Platform* platform) {
   Platform::Initialize(platform);
 
-  V8Initializer::InitializeMainThread();
+  // Refernce table must be updated before creating isolates.
+  V8SnapshotCreator::SetReferenceTable(

[Yuki, 2017/06/01 14:15:51]

Can we put this into InitializeMainThread() considering that V8Initializer
should be responsible all V8-related initialization?

[peria, 2017/06/20 10:20:14]

No, we can't.
V8Initializer is under core/, and V8SnapshotExternalReferences is under module/.
And what this line does must be a part of GetModulesInitializer().Initialize()
(2 lines below), but this work must be done before isolates' instantiation.

+      V8SnapshotExternalReferences::GetTable());
+  V8Initializer::InitializeMainThread(platform->TakeV8Snapshot());

[Yuki, 2017/06/01 14:15:51]

Can we simply pass |platform| and let InitliazeMainThread take care of the rest?

  V8Initializer::InitializeMainThread(platform);

looks simpler to me.

[peria, 2017/06/20 10:20:14]

Done.
I found we can call platform via Platform::Current(), so we don't need to pass
it here.

 
   GetModulesInitializer().Initialize();