Revert "Change call-sites now that SkCanvas is not ref-counted"

ppapi/proxy/ppb_image_data_proxy.h

 // 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.
 
 #ifndef PPAPI_PPB_IMAGE_DATA_PROXY_H_
 #define PPAPI_PPB_IMAGE_DATA_PROXY_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 86 matching lines @@
   void Unmap() override;
   SkCanvas* GetPlatformCanvas() override;
   SkCanvas* GetCanvas() override;
 
   static ImageHandle NullHandle();
 
  private:
   std::unique_ptr<TransportDIB> transport_dib_;
 
   // Null when the image isn't mapped.
-  std::unique_ptr<SkCanvas> mapped_canvas_;
+  sk_sp<SkCanvas> mapped_canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformImageData);
 };
 #endif  // !defined(OS_NACL)
 
 // SimpleImageData is a simple, platform-independent image data resource which
 // can be used by NaCl. It can also be used by trusted apps when access to the
 // platform canvas isn't needed.
 class PPAPI_PROXY_EXPORT SimpleImageData : public ImageData {
  public:
@@ skipping 73 matching lines @@
   // Host->Plugin message handlers.
   void OnPluginMsgNotifyUnusedImageData(const HostResource& old_image_data);
 
   DISALLOW_COPY_AND_ASSIGN(PPB_ImageData_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PPB_IMAGE_DATA_PROXY_H_