Optionally clear PlatformCanvas instances.

skia/ext/skia_utils_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "skia/ext/skia_utils_mac.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
@@ skipping 184 matching lines @@
 }
 
 SkBitmap CGImageToSkBitmap(CGImageRef image) {
   if (!image)
     return SkBitmap();
 
   int width = CGImageGetWidth(image);
   int height = CGImageGetHeight(image);
 
   scoped_ptr<SkDevice> device(
-      skia::BitmapPlatformDevice::Create(NULL, width, height, false));
+      skia::BitmapPlatformDevice::Create(NULL, width, height, 
+                                         skia::PlatformDevice::FLAGS_NONE));
 
   CGContextRef context = skia::GetBitmapContext(device.get());
 
   // We need to invert the y-axis of the canvas so that Core Graphics drawing
   // happens right-side up. Skia has an upper-left origin and CG has a lower-
   // left one.
   CGContextScaleCTM(context, 1.0, -1.0);
   CGContextTranslateCTM(context, 0, -height);
 
   // We want to copy transparent pixels from |image|, instead of blending it
@@ skipping 140 matching lines @@
   // Apply content matrix.
   SkMatrix skMatrix = canvas_->getTotalMatrix();
   skMatrix.postTranslate(-SkIntToScalar(pt.fX), -SkIntToScalar(pt.fY));
   CGAffineTransform affine = SkMatrixToCGAffineTransform(skMatrix);
   CGContextConcatCTM(cgContext_, affine);
   
   return cgContext_;
 }
 
 }  // namespace gfx