Implementing FlushMappedBufferRange in GPU command buffer.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
index 7d30822d5744ad0a6b71b503eccdc4d2a8c192a8..7f595d05d1d52bc6fe9e461a40f917005fd4aec7 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
@@ -711,6 +711,13 @@ error::Error GLES2DecoderPassthroughImpl::DoFlush() {
   return error::kNoError;
 }
 
+error::Error GLES2DecoderPassthroughImpl::DoFlushMappedBufferRange(
+    GLenum target,
+    GLintptr offset,
+    GLsizeiptr size) {
+  return error::kNoError;
+}
+
 error::Error GLES2DecoderPassthroughImpl::DoFramebufferRenderbuffer(
     GLenum target,
     GLenum attachment,