Submit CompositorFrame from worker

third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp

Index: third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
diff --git a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
index 9a149bbeeb97bf6e28e7a86e60883c881e0ad551..4f805106e6c2e15e2056075a2f0e9ef421ec8adf 100644
--- a/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp
@@ -44,12 +44,13 @@ DEFINE_TRACE(OffscreenCanvasRenderingContext2D)
     BaseRenderingContext2D::trace(visitor);
 }
 
-void OffscreenCanvasRenderingContext2D::commit(ExecutionContext* executionContext)
+void OffscreenCanvasRenderingContext2D::commit(ExceptionState& exceptionState)
 {
-    if (executionContext->isWorkerGlobalScope()) {
-        // TODO(xlai): implement commit() on worker thread; currently, do
-        // nothing for worker thread. See crbug.com/563858.
-        return;
+    if (getOffscreenCanvas()->getAssociatedCanvasId() < 0) {
+        // If an OffscreenCanvas has no associated canvas Id, it indicates that
+        // it is not an OffscreenCanvas created by transfering control from html
+        // canvas.
+        exceptionState.throwDOMException(InvalidStateError, "Commit() has no effect if HTMLCanvasElement.transferControlToOffscreen() is not called.");

[Justin Novosad, 2016/09/07 21:40:15]

This message is not true: there is an effect, an exception is thrown.  I think
the message would be clearer like this: "commit() was called on a context whose
OffscreenCanvas is not associated with an canvas element."

[xlai (Olivia), 2016/09/08 15:27:15]

Done.

     }
     getOffscreenCanvas()->getOrCreateFrameDispatcher()->dispatchFrame();
 }