Sharing of SharedArrayBuffer via PostMessage transfer

Source/core/dom/DOMTypedArray.cpp

Index: Source/core/dom/DOMTypedArray.cpp
diff --git a/Source/core/dom/DOMTypedArray.cpp b/Source/core/dom/DOMTypedArray.cpp
index c5d5e327d018c255fc63682c4ee9b7566ddf929b..025184cb2a4f59db581824195641e6ab2cc5eb68 100644
--- a/Source/core/dom/DOMTypedArray.cpp
+++ b/Source/core/dom/DOMTypedArray.cpp
@@ -31,13 +31,19 @@ v8::Local<v8::Object> DOMTypedArray<WTFTypedArray, V8TypedArray>::wrap(v8::Isola
     ASSERT(!DOMDataStore::containsWrapper(this, isolate));
 
     const WrapperTypeInfo* wrapperTypeInfo = this->wrapperTypeInfo();
-    RefPtr<DOMArrayBuffer> buffer = this->buffer();
-    v8::Local<v8::Value> v8Buffer = toV8(buffer.get(), creationContext, isolate);
+    v8::Local<v8::Value> v8Buffer;
+    RefPtr<DOMArrayBufferBase> buffer = this->bufferBase();
+    v8Buffer = toV8(buffer.get(), creationContext, isolate);

[Yuki, 2015/06/10 07:44:55]

nit: You can write as follows.  Initialization at declaration is preferred.

v8::Local<v8::Value> v8Buffer = toV8(...);

[binji, 2015/06/10 20:53:40]

Done.

+    ASSERT(isShared() == v8Buffer->IsSharedArrayBuffer());

[Yuki, 2015/06/10 07:44:55]

This line and below should be swapped, otherwise you'll access to the empty
handle's member.

if (v8Buffer.IsEmpty())
    return ...;
ASSERT(isShared() == v8Buffer->IsSharedArrayBuffer());

[binji, 2015/06/10 20:53:40]

Done.

     if (v8Buffer.IsEmpty())
-        return v8::Handle<v8::Object>();
-    ASSERT(v8Buffer->IsArrayBuffer());
+        return v8::Local<v8::Object>();
 
-    v8::Local<v8::Object> wrapper = V8TypedArray::New(v8Buffer.As<v8::ArrayBuffer>(), byteOffset(), length());
+    v8::Local<v8::Object> wrapper;
+    if (isShared()) {
+        wrapper = V8TypedArray::New(v8Buffer.As<v8::ArrayBuffer>(), byteOffset(), length());
+    } else {
+        wrapper = V8TypedArray::New(v8Buffer.As<v8::SharedArrayBuffer>(), byteOffset(), length());
+    }
 
     return associateWithWrapper(isolate, wrapperTypeInfo, wrapper);
 }