Convert ppapi/shared to use TrackedCallback.

ppapi/proxy/ppb_video_decoder_proxy.cc

Index: ppapi/proxy/ppb_video_decoder_proxy.cc
diff --git a/ppapi/proxy/ppb_video_decoder_proxy.cc b/ppapi/proxy/ppb_video_decoder_proxy.cc
index 850ae6e51db0092b1f2e229a700490ed72df04b6..3f5cdc418530b6f915656d7511799c2f8bfc8ef9 100644
--- a/ppapi/proxy/ppb_video_decoder_proxy.cc
+++ b/ppapi/proxy/ppb_video_decoder_proxy.cc
@@ -23,7 +23,7 @@ using ppapi::thunk::PPB_VideoDecoder_API;
 namespace ppapi {
 namespace proxy {
 
-class VideoDecoder : public Resource, public PPB_VideoDecoder_Shared {
+class VideoDecoder : public PPB_VideoDecoder_Shared {
  public:
   // You must call Init() before using this class.
   explicit VideoDecoder(const HostResource& resource);
@@ -33,9 +33,6 @@ class VideoDecoder : public Resource, public PPB_VideoDecoder_Shared {
                               PP_Resource graphics_context,
                               PP_VideoDecoder_Profile profile);
 
-  // Resource overrides.
-  virtual PPB_VideoDecoder_API* AsPPB_VideoDecoder_API() OVERRIDE;
-
   // PPB_VideoDecoder_API implementation.
   virtual int32_t Decode(const PP_VideoBitstreamBuffer_Dev* bitstream_buffer,
                          PP_CompletionCallback callback) OVERRIDE;
@@ -59,16 +56,13 @@ class VideoDecoder : public Resource, public PPB_VideoDecoder_Shared {
   DISALLOW_COPY_AND_ASSIGN(VideoDecoder);
 };
 
-VideoDecoder::VideoDecoder(const HostResource& decoder) : Resource(decoder) {
+VideoDecoder::VideoDecoder(const HostResource& decoder)
+    : PPB_VideoDecoder_Shared(decoder) {
 }
 
 VideoDecoder::~VideoDecoder() {
 }
 
-PPB_VideoDecoder_API* VideoDecoder::AsPPB_VideoDecoder_API() {
-  return this;
-}
-
 int32_t VideoDecoder::Decode(
     const PP_VideoBitstreamBuffer_Dev* bitstream_buffer,
     PP_CompletionCallback callback) {