Remove SupportsWeakPtr inheritance from GLES2Decoder

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
index 24e5f60dbc92fbc66edda2f022671b3b986abc34..ef93a906d57da8977c7ca7f53580d772a585484a 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
@@ -78,7 +78,8 @@ GLES2DecoderPassthroughImpl::GLES2DecoderPassthroughImpl(ContextGroup* group)
       context_(),
       offscreen_(false),
       group_(group),
-      feature_info_(new FeatureInfo) {
+      feature_info_(new FeatureInfo),
+      weak_ptr_factory_(this) {
   DCHECK(group);
 }
 
@@ -153,6 +154,10 @@ const char* GLES2DecoderPassthroughImpl::GetCommandName(
   return GetCommonCommandName(static_cast<cmd::CommandId>(command_id));
 }
 
+base::WeakPtr<GLES2Decoder> GLES2DecoderPassthroughImpl::AsWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
+}
+
 bool GLES2DecoderPassthroughImpl::Initialize(
     const scoped_refptr<gl::GLSurface>& surface,
     const scoped_refptr<gl::GLContext>& context,