Add a second unsafe ES3 API in command buffer.

gpu/command_buffer/client/gles2_trace_implementation_autogen.h

Index: gpu/command_buffer/client/gles2_trace_implementation_autogen.h
diff --git a/gpu/command_buffer/client/gles2_trace_implementation_autogen.h b/gpu/command_buffer/client/gles2_trace_implementation_autogen.h
index 4931e64574418fdacfd459efe2d918c7d8f6b3b5..51fec37ff71cfec5157d051774dc0d43690a813c 100644
--- a/gpu/command_buffer/client/gles2_trace_implementation_autogen.h
+++ b/gpu/command_buffer/client/gles2_trace_implementation_autogen.h
@@ -70,6 +70,11 @@ void CompressedTexSubImage2D(GLenum target,
                              GLenum format,
                              GLsizei imageSize,
                              const void* data) override;
+void CopyBufferSubData(GLenum readtarget,
+                       GLenum writetarget,
+                       GLintptr readoffset,
+                       GLintptr writeoffset,
+                       GLsizeiptr size) override;
 void CopyTexImage2D(GLenum target,
                     GLint level,
                     GLenum internalformat,