Implement TransformFeedbackManager in GPU command buffer.

gpu/command_buffer/service/context_group.cc

Index: gpu/command_buffer/service/context_group.cc
diff --git a/gpu/command_buffer/service/context_group.cc b/gpu/command_buffer/service/context_group.cc
index 18d315ede33b78d6e7dd841e824528e737d8c235..9532c321de583fc51f08a00e5195c71f97cc0c1e 100644
--- a/gpu/command_buffer/service/context_group.cc
+++ b/gpu/command_buffer/service/context_group.cc
@@ -22,6 +22,7 @@
 #include "gpu/command_buffer/service/shader_manager.h"
 #include "gpu/command_buffer/service/texture_manager.h"
 #include "gpu/command_buffer/service/transfer_buffer_manager.h"
+#include "gpu/command_buffer/service/transform_feedback_manager.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_version_info.h"
 
@@ -206,6 +207,8 @@ bool ContextGroup::Initialize(GLES2Decoder* decoder,
       feature_info_.get()));
   shader_manager_.reset(new ShaderManager());
   sampler_manager_.reset(new SamplerManager(feature_info_.get()));
+  transform_feedback_manager_.reset(new TransformFeedbackManager(
+      max_transform_feedback_separate_attribs_));
 
   // Lookup GL things we need to know.
   const GLint kGLES2RequiredMinimumVertexAttribs = 8u;
@@ -512,6 +515,11 @@ void ContextGroup::Destroy(GLES2Decoder* decoder, bool have_context) {
     sampler_manager_.reset();
   }
 
+  if (transform_feedback_manager_ != NULL) {
+    transform_feedback_manager_->Destroy(have_context);
+    transform_feedback_manager_.reset();
+  }
+
   memory_tracker_ = NULL;
 }