Change GraphicsContext::createCompatibleBuffer to return something non-null

Source/platform/graphics/GraphicsContext.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google 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
@@ skipping 1615 matching lines @@
             p1.setX(p1.x() + 0.5f);
             p2.setX(p2.x() + 0.5f);
         } else {
             // We're a horizontal line. Adjust our y.
             p1.setY(p1.y() + 0.5f);
             p2.setY(p2.y() + 0.5f);
         }
     }
 }
 
-PassOwnPtr<ImageBuffer> GraphicsContext::createCompatibleBuffer(const IntSize& size, OpacityMode opacityMode) const
+PassOwnPtr<ImageBuffer> GraphicsContext::createRasterBuffer(const IntSize& size, OpacityMode opacityMode) const
 {
     // Make the buffer larger if the context's transform is scaling it so we need a higher
     // resolution than one pixel per unit. Also set up a corresponding scale factor on the
     // graphics context.
 
     AffineTransform transform = getCTM();
     IntSize scaledSize(static_cast<int>(ceil(size.width() * transform.xScale())), static_cast<int>(ceil(size.height() * transform.yScale())));
 
     SkAlphaType alphaType = (opacityMode == Opaque) ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
     SkImageInfo info = SkImageInfo::MakeN32(size.width(), size.height(), alphaType);
-    RefPtr<SkSurface> skSurface = adoptRef(m_canvas->newSurface(info));
+    RefPtr<SkSurface> skSurface = adoptRef(SkSurface::NewRaster(info));
     if (!skSurface)
         return nullptr;
     OwnPtr<ImageBufferSurface> surface = adoptPtr(new CompatibleImageBufferSurface(skSurface.release(), scaledSize, opacityMode));
     ASSERT(surface->isValid());
     OwnPtr<ImageBuffer> buffer = adoptPtr(new ImageBuffer(surface.release()));
 
     buffer->context()->scale(static_cast<float>(scaledSize.width()) / size.width(),
         static_cast<float>(scaledSize.height()) / size.height());
 
     return buffer.release();
@@ skipping 168 matching lines @@
 
 void GraphicsContext::didDrawTextInRect(const SkRect& textRect)
 {
     if (m_trackTextRegion) {
         TRACE_EVENT0("skia", "GraphicsContext::didDrawTextInRect");
         m_textRegion.join(textRect);
     }
 }
 
 }