Add glTransformFeedbackVaryings to GPU command buffer.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 13b10c5ee8346f9d4d0f3130813261a37f61549a..d6ce51d046b3fb3f8754900f4dcd17edc151fb6d 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1178,6 +1178,11 @@ class GLES2DecoderImpl : public GLES2Decoder,
   void DoShaderSource(
       GLuint client_id, GLsizei count, const char** data, const GLint* length);
 
+  // Wrapper for glTransformFeedbackVaryings.
+  void DoTransformFeedbackVaryings(
+      GLuint client_program_id, GLsizei count, const char* const* varyings,
+      GLenum buffer_mode);
+
   // Clear any textures used by the current program.
   bool ClearUnclearedTextures();
 
@@ -7057,6 +7062,18 @@ void GLES2DecoderImpl::DoShaderSource(
   shader->set_source(str);
 }
 
+void GLES2DecoderImpl::DoTransformFeedbackVaryings(
+    GLuint client_program_id, GLsizei count, const char* const* varyings,
+    GLenum buffer_mode) {
+  Program* program = GetProgramInfoNotShader(
+      client_program_id, "glTransformFeedbackVaryings");
+  if (!program) {
+    return;
+  }
+  glTransformFeedbackVaryings(
+      program->service_id(), count, varyings, buffer_mode);
+}
+
 void GLES2DecoderImpl::DoCompileShader(GLuint client_id) {
   TRACE_EVENT0("gpu", "GLES2DecoderImpl::DoCompileShader");
   Shader* shader = GetShaderInfoNotProgram(client_id, "glCompileShader");