IDL: Add [FlexibleArrayBufferView] and use for bufferSubData

Source/bindings/core/v8/V8Binding.h

Index: Source/bindings/core/v8/V8Binding.h
diff --git a/Source/bindings/core/v8/V8Binding.h b/Source/bindings/core/v8/V8Binding.h
index 8cdce0b341093efc08197aca973d6d1b1ea688a3..fd6b8518ab2726981d2e59d7f6c690f4341a5a99 100644
--- a/Source/bindings/core/v8/V8Binding.h
+++ b/Source/bindings/core/v8/V8Binding.h
@@ -62,6 +62,7 @@ class LocalDOMWindow;
 class LocalFrame;
 class NodeFilter;
 class XPathNSResolver;
+class FlexibleArrayBufferView;
 
 template <typename T>
 struct V8TypeOf {
@@ -897,6 +898,12 @@ CORE_EXPORT Frame* toFrameIfNotDetached(v8::Handle<v8::Context>);
 
 CORE_EXPORT EventTarget* toEventTarget(v8::Isolate*, v8::Handle<v8::Value>);
 
+// If 'storage' is non-null, it must be large enough to copy all bytes in the
+// array buffer view into it.
+// Use SMALL_ARRAY_BUFFER_VIEW_STORAGE(v8Value) to allocate it using alloca() in
+// the callers stack frame.
+CORE_EXPORT void toFlexibleArrayBufferView(v8::Isolate*, v8::Handle<v8::Value>, FlexibleArrayBufferView&, void* storage = nullptr);
+
 // If the current context causes out of memory, JavaScript setting
 // is disabled and it returns true.
 bool handleOutOfMemory();