Introduce FlexibleArrayBufferView and TypedFlexibleArrayBufferView

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 aaae3c39d62a77275436e04a2ec991a34b27146f..71f6947fabcc96871cc86406fd2f2858ca30c1ce 100644
--- a/Source/bindings/core/v8/V8Binding.h
+++ b/Source/bindings/core/v8/V8Binding.h
@@ -57,6 +57,7 @@ class EventListener;
 class EventTarget;
 class ExceptionState;
 class ExecutionContext;
+class FlexibleArrayBufferView;
 class Frame;
 class LocalDOMWindow;
 class LocalFrame;
@@ -973,6 +974,11 @@ CORE_EXPORT Frame* toFrameIfNotDetached(v8::Local<v8::Context>);
 
 CORE_EXPORT EventTarget* toEventTarget(v8::Isolate*, v8::Local<v8::Value>);
 
+// If 'storage' is non-null, it must be large enough to copy all bytes in the
+// array buffer view into it.  Use allocateFlexibleArrayBufferStorage(v8Value)
+// to allocate it using alloca() in the callers stack frame.
+CORE_EXPORT void toFlexibleArrayBufferView(v8::Isolate*, v8::Local<v8::Value>, FlexibleArrayBufferView&, void* storage = nullptr);
+
 // If the current context causes out of memory, JavaScript setting
 // is disabled and it returns true.
 bool handleOutOfMemory();