Implement WebGL's commit on the main thread

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
index fa89b61043337bef639bdfac0d77ade1298c2e68..e89db0777892b39cdb65680483d63fa70bb55ef2 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -649,6 +649,22 @@ ImageBitmap* WebGLRenderingContextBase::transferToImageBitmapBase()
     return ImageBitmap::create(drawingBuffer()->transferToStaticBitmapImage());
 }
 
+void WebGLRenderingContextBase::commit(ExceptionState& exceptionState)
+{
+    if (!getOffscreenCanvas()) {
+        exceptionState.throwDOMException(InvalidStateError, "No OffscreenCanvas exist, abort commit().");

[xlai (Olivia), 2016/09/09 20:30:41]

Could you add a sub-test to OffscreenCanvas-commit-invalid-call.html for this
exception msg?

[Ken Russell (switch to Gerrit), 2016/09/09 21:38:17]

Also, nit: exist -> exists

+        return;
+    }
+    // no HTMLCanvas associated, thrown InvalidStateError
+    if (getOffscreenCanvas()->getAssociatedCanvasId() == -1) {
+        exceptionState.throwDOMException(InvalidStateError, "The OffscreenCanvas has no associated HTMLCanvasElement, abort commit().");

[xlai (Olivia), 2016/09/09 20:30:41]

Could you change the exception message to "Commit() was called on a context
whose OffscreenCanvas is not associated with a canvas element."? 
This is to be consistent with the 2d context error msg.

+        return;
+    }
+    if (!drawingBuffer())
+        return;
+    getOffscreenCanvas()->getOrCreateFrameDispatcher()->dispatchFrame(drawingBuffer()->transferToStaticBitmapImage());
+}
+
 PassRefPtr<Image> WebGLRenderingContextBase::getImage(AccelerationHint hint, SnapshotReason reason) const
 {
     if (!drawingBuffer())