Refactor CRC2D::reset() to avoid non-additive SkCanvas state operations

third_party/WebKit/Source/platform/graphics/gpu/AcceleratedImageBufferSurface.cpp

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
   CHECK(grContext);
 
   SkAlphaType alphaType =
       (Opaque == opacityMode) ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
   SkImageInfo info =
       SkImageInfo::MakeN32(size.width(), size.height(), alphaType);
   SkSurfaceProps disableLCDProps(0, kUnknown_SkPixelGeometry);
   m_surface = SkSurface::MakeRenderTarget(
       grContext, SkBudgeted::kYes, info, 0 /* sampleCount */,
       Opaque == opacityMode ? nullptr : &disableLCDProps);
-  if (!m_surface.get())
+  if (!m_surface)
     return;
   clear();
+
+  // Always save an initial frame, to support resetting the top level matrix
+  // and clip.
+  m_surface->getCanvas()->save();
 }
 
 bool AcceleratedImageBufferSurface::isValid() const {
   return m_surface && SharedGpuContext::isValid() &&
          m_contextId == SharedGpuContext::contextId();
 }
 
 sk_sp<SkImage> AcceleratedImageBufferSurface::newImageSnapshot(AccelerationHint,
                                                                SnapshotReason) {
   return m_surface->makeImageSnapshot();
 }
 
 GLuint AcceleratedImageBufferSurface::getBackingTextureHandleForOverwrite() {
   if (!m_surface)
     return 0;
   return skia::GrBackendObjectToGrGLTextureInfo(
              m_surface->getTextureHandle(
                  SkSurface::kDiscardWrite_TextureHandleAccess))
       ->fID;
 }
 
 }  // namespace blink