Make OffscreenCanvasRenderingContext2D renderable on a worker

third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvas.cpp

Index: third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvas.cpp
diff --git a/third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvas.cpp b/third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvas.cpp
index df103939b734876ec2e0a55e7ed0fdbbd6e213da..d63ae1124067c94e07df2085f91ec87235ee7665 100644
--- a/third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvas.cpp
+++ b/third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvas.cpp
@@ -4,6 +4,10 @@
 
 #include "modules/offscreencanvas/OffscreenCanvas.h"
 
+#include "core/dom/ExceptionCode.h"
+#if !ENABLE(OILPAN)
+#include "core/frame/ImageBitmap.h" // So ~RefPtr can call unref()
+#endif
 #include "core/html/canvas/CanvasContextCreationAttributes.h"
 #include "modules/offscreencanvas/OffscreenCanvasRenderingContext.h"
 #include "modules/offscreencanvas/OffscreenCanvasRenderingContextFactory.h"
@@ -12,6 +16,13 @@
 
 namespace blink {
 
+OffscreenCanvas::OffscreenCanvas(const IntSize& size)
+    : m_size(size)
+{ }
+
+OffscreenCanvas::~OffscreenCanvas()
+{ }
+
 OffscreenCanvas* OffscreenCanvas::create(unsigned width, unsigned height)
 {
     return new OffscreenCanvas(IntSize(clampTo<int>(width), clampTo<int>(height)));
@@ -27,11 +38,6 @@ void OffscreenCanvas::setHeight(unsigned height)
     m_size.setHeight(clampTo<int>(height));
 }
 
-OffscreenCanvas::OffscreenCanvas(const IntSize& size)
-    : m_size(size)
-{
-}
-
 OffscreenCanvasRenderingContext2D* OffscreenCanvas::getContext(const String& id, const CanvasContextCreationAttributes& attributes)
 {
     OffscreenCanvasRenderingContext::ContextType contextType = OffscreenCanvasRenderingContext::contextTypeFromId(id);
@@ -59,6 +65,20 @@ OffscreenCanvasRenderingContext2D* OffscreenCanvas::getContext(const String& id,
     return static_cast<OffscreenCanvasRenderingContext2D*>(m_context.get());
 }
 
+PassRefPtrWillBeRawPtr<ImageBitmap> OffscreenCanvas::transferToImageBitmap(ExceptionState& exceptionState)
+{
+    if (!m_context) {
+        exceptionState.throwDOMException(InvalidStateError, "Cannot transfer an ImageBitmap from an OffscreenCanvas with no context");
+        return nullptr;
+    }
+    RefPtrWillBeRawPtr<ImageBitmap> image = m_context->transferToImageBitmap(exceptionState);
+    if (!image) {
+        // Undocumented exception (not in spec)
+        exceptionState.throwDOMException(V8GeneralError, "Out of memory");
+    }
+    return image.release();
+}
+
 OffscreenCanvasRenderingContext2D* OffscreenCanvas::renderingContext() const
 {
     // TODO: When there're more than one context type implemented in the future,