Stop OffscreenCanvas resize from changing placeholder attributes

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 159 matching lines @@
   return HTMLElement::createLayoutObject(style);
 }
 
 Node::InsertionNotificationRequest HTMLCanvasElement::insertedInto(
     ContainerNode* node) {
   setIsInCanvasSubtree(true);
   return HTMLElement::insertedInto(node);
 }
 
 void HTMLCanvasElement::setHeight(int value, ExceptionState& exceptionState) {
-  if (surfaceLayerBridge()) {
-    // The existence of surfaceLayerBridge indicates that
-    // canvas.transferControlToOffscreen has been called.
-    exceptionState.throwDOMException(InvalidStateError,
-                                     "Resizing is not allowed for a canvas "
-                                     "that has transferred its control to "
-                                     "offscreen.");
-    return;
-  }
   setIntegralAttribute(heightAttr, value);
 }
 
 void HTMLCanvasElement::setWidth(int value, ExceptionState& exceptionState) {
-  if (surfaceLayerBridge()) {
-    // Same comment as above.
-    exceptionState.throwDOMException(InvalidStateError,
-                                     "Resizing is not allowed for a canvas "
-                                     "that has transferred its control to "
-                                     "offscreen.");
-    return;
-  }
   setIntegralAttribute(widthAttr, value);
 }
 
 void HTMLCanvasElement::setSize(const IntSize& newSize) {
   if (newSize == size())
     return;
   m_ignoreReset = true;
   setIntegralAttribute(widthAttr, newSize.width());
   setIntegralAttribute(heightAttr, newSize.height());
   m_ignoreReset = false;
@@ skipping 1048 matching lines @@
 FloatSize HTMLCanvasElement::elementSize(const FloatSize&) const {
   if (m_context &&
       m_context->getContextType() ==
           CanvasRenderingContext::ContextImageBitmap) {
     RefPtr<Image> image =
         m_context->getImage(PreferNoAcceleration, SnapshotReasonDrawImage);
     if (image)
       return FloatSize(image->width(), image->height());
     return FloatSize(0, 0);
   }
+  if (placeholderFrame())
+    return FloatSize(placeholderFrame()->size());
   return FloatSize(width(), height());
 }
 
 IntSize HTMLCanvasElement::bitmapSourceSize() const {
   return IntSize(width(), height());
 }
 
 ScriptPromise HTMLCanvasElement::createImageBitmap(
     ScriptState* scriptState,
     EventTarget& eventTarget,
@@ skipping 104 matching lines @@
   mojom::blink::OffscreenCanvasSurfacePtr service;
   Platform::current()->interfaceProvider()->getInterface(
       mojo::GetProxy(&service));
   m_surfaceLayerBridge =
       wrapUnique(new CanvasSurfaceLayerBridge(std::move(service)));
   return m_surfaceLayerBridge->createSurfaceLayer(this->width(),
                                                   this->height());
 }
 
 }  // namespace blink