Add ImageBitmapRenderingContext (experimental)

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

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
index 51ad64568734c0db8969c0b6ee5d4b1e86923de3..8ade02136e791477f64040698a2a5e53a8cb4ace 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -335,7 +335,7 @@ void HTMLCanvasElement::restoreCanvasMatrixClipStack(SkCanvas* canvas) const
 void HTMLCanvasElement::doDeferredPaintInvalidation()
 {
     ASSERT(!m_dirtyRect.isEmpty());
-    if (is3D()) {
+    if (!m_context->is2d()) {
         didFinalizeFrame();
     } else {
         ASSERT(hasImageBuffer());
@@ -461,6 +461,12 @@ void HTMLCanvasElement::paint(GraphicsContext& context, const LayoutRect& r)
     if (!paintsIntoCanvasBuffer() && !document().printing())
         return;
 
+    // TODO(junov): Paint is currently only implemented by ImageBitmap contexts,

[Stephen White, 2016/02/10 15:34:55]

MicroNit: comma splice. Use a semicolon, or split into two sentences.

+    // we could improve the abstraction by making all context types paint
+    /// themselves (implement paint).

[Stephen White, 2016/02/10 15:34:55]

MicroNit: ///

+    if (m_context->paint(context, pixelSnappedIntRect(r)))
+        return;
+
     m_context->paintRenderingResultsToCanvas(FrontBuffer);
     if (hasImageBuffer()) {
         if (!context.contextDisabled()) {