Avoid unnecessary clipping of gradient/generated images

third_party/WebKit/Source/platform/graphics/GradientGeneratedImage.cpp

 /*
  * Copyright (C) 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 14 matching lines @@
 
 #include "platform/graphics/GradientGeneratedImage.h"
 
 #include "platform/geometry/FloatRect.h"
 #include "platform/graphics/GraphicsContext.h"
 
 namespace blink {
 
 void GradientGeneratedImage::draw(SkCanvas* canvas, const SkPaint& paint, const FloatRect& destRect, const FloatRect& srcRect, RespectImageOrientationEnum, ImageClampingMode)
 {
-    SkAutoCanvasRestore ar(canvas, true);
-    canvas->clipRect(destRect);
-    canvas->translate(destRect.x(), destRect.y());
-    if (destRect.size() != srcRect.size())
-        canvas->scale(destRect.width() / srcRect.width(), destRect.height() / srcRect.height());
-    canvas->translate(-srcRect.x(), -srcRect.y());
+    SkRect visibleRect = srcRect;
+    if (!visibleRect.intersect(SkRect::MakeIWH(m_size.width(), m_size.height())))
+        return;
+
+    SkMatrix transform = SkMatrix::MakeRectToRect(srcRect, destRect, SkMatrix::kFill_ScaleToFit);
+    SkAutoCanvasRestore autoRestore(canvas, !transform.isIdentity());
+    canvas->concat(transform);
+
     SkPaint gradientPaint(paint);
     m_gradient->applyToPaint(gradientPaint);
-    canvas->drawRect(SkRect::MakeWH(m_size.width(), m_size.height()), gradientPaint);
+
+    canvas->drawRect(visibleRect, gradientPaint);
 }
 
 void GradientGeneratedImage::drawTile(GraphicsContext& context, const FloatRect& srcRect)
 {
     context.setFillGradient(m_gradient);
     context.fillRect(srcRect);
 }
 
 } // namespace blink