Refactoring Canvas2DLayerBridge to make it easier to write unit tests

Source/core/platform/graphics/ImageBuffer.cpp

 /*
  * Copyright (c) 2008, Google Inc. All rights reserved.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 43 matching lines @@
 #include "third_party/skia/include/gpu/GrContext.h"
 #include "third_party/skia/include/gpu/SkGpuDevice.h"
 #include "wtf/MathExtras.h"
 #include "wtf/text/Base64.h"
 #include "wtf/text/WTFString.h"
 
 using namespace std;
 
 namespace WebCore {
 
+namespace {
+
+class AcceleratedLayerHelper : public Canvas2DLayerBridge::Helper {
+public:
+    virtual PassRefPtr<GraphicsContext3D> getContext() OVERRIDE
+    {
+        return SharedGraphicsContext3D::get();
+    }
+
+    virtual SkSurface* createSurface(GraphicsContext3D* context3D, const IntSize& size) OVERRIDE
+    {
+        ASSERT(!context3D->webContext()->isContextLost());
+        GrContext* gr = context3D->grContext();
+        if (!gr)
+            return 0;
+        gr->resetContext();
+        SkImage::Info info;
+        info.fWidth = size.width();
+        info.fHeight = size.height();
+        info.fColorType = SkImage::kPMColor_ColorType;
+        info.fAlphaType = SkImage::kPremul_AlphaType;
+        return SkSurface::NewRenderTarget(gr, info);
+    }
+};
+
+} // unnamed namespace
+
 static SkCanvas* createAcceleratedCanvas(const IntSize& size, OwnPtr<Canvas2DLayerBridge>* outLayerBridge, OpacityMode opacityMode)
 {
-    RefPtr<GraphicsContext3D> context3D = SharedGraphicsContext3D::get();
-    if (!context3D)
+    OwnPtr<AcceleratedLayerHelper> helper = adoptPtr(new AcceleratedLayerHelper);
+    if (!helper->getContext())
         return 0;
     Canvas2DLayerBridge::OpacityMode bridgeOpacityMode = opacityMode == Opaque ? Canvas2DLayerBridge::Opaque : Canvas2DLayerBridge::NonOpaque;
-    *outLayerBridge = Canvas2DLayerBridge::create(context3D.release(), size, bridgeOpacityMode);
+    *outLayerBridge = Canvas2DLayerBridge::create(helper.release(), size, bridgeOpacityMode);
     // If canvas buffer allocation failed, debug build will have asserted
     // For release builds, we must verify whether the device has a render target
     return (*outLayerBridge) ? (*outLayerBridge)->getCanvas() : 0;
 }
 
 static SkCanvas* createNonPlatformCanvas(const IntSize& size)
 {
     SkAutoTUnref<SkDevice> device(new SkDevice(SkBitmap::kARGB_8888_Config, size.width(), size.height()));
     SkPixelRef* pixelRef = device->accessBitmap(false).pixelRef();
     return pixelRef ? new SkCanvas(device) : 0;
@@ skipping 408 matching lines @@
     if (!encodeImage(imageData, mimeType, quality, &encodedImage))
         return "data:,";
 
     Vector<char> base64Data;
     base64Encode(encodedImage, base64Data);
 
     return "data:" + mimeType + ";base64," + base64Data;
 }
 
 } // namespace WebCore