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 95e07416683a6e2fab96e5c131e4d69a8379e0df..15f814c38c393fe23550fbc11cadd2ae3786e230 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -650,6 +650,23 @@ ImageBitmap* WebGLRenderingContextBase::transferToImageBitmapBase()
     return ImageBitmap::create(drawingBuffer()->transferToStaticBitmapImage());
 }
 
+void WebGLRenderingContextBase::commit(ExceptionState& exceptionState)
+{
+    if (!getOffscreenCanvas()) {
+        exceptionState.throwDOMException(InvalidStateError, "Commit() was called on a rendering context that was not created from an OffscreenCanvas.");
+        return;
+    }
+    // no HTMLCanvas associated, thrown InvalidStateError
+    if (getOffscreenCanvas()->getAssociatedCanvasId() == -1) {
+        exceptionState.throwDOMException(InvalidStateError, "Commit() was called on a context whose OffscreenCanvas is not associated with a canvas element.");
+        return;
+    }
+    if (!drawingBuffer())
+        return;
+    // TODO(crbug.com/646864): Make commit() work correctly with { preserveDrawingBuffer : true }.
+    getOffscreenCanvas()->getOrCreateFrameDispatcher()->dispatchFrame(std::move(drawingBuffer()->transferToStaticBitmapImage()));
+}
+
 PassRefPtr<Image> WebGLRenderingContextBase::getImage(AccelerationHint hint, SnapshotReason reason) const
 {
     if (!drawingBuffer())