Add glClientWaitSync 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 52a9c4351b47185261d76eba400f20aec9bb0b41..fe8137312fffcc7786e5ac5af0c931a9ffd38e07 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -12055,6 +12055,33 @@ error::Error GLES2DecoderImpl::HandleUniformBlockBinding(
   return error::kNoError;
 }
 
+error::Error GLES2DecoderImpl::HandleClientWaitSync(
+    uint32_t immediate_data_size, const void* cmd_data) {
+  if (!unsafe_es3_apis_enabled())
+    return error::kUnknownCommand;
+  const gles2::cmds::ClientWaitSync& c =
+      *static_cast<const gles2::cmds::ClientWaitSync*>(cmd_data);
+  GLuint sync = static_cast<GLuint>(c.sync);
+  GLbitfield flags = static_cast<GLbitfield>(c.flags);
+  GLuint64 timeout = GLES2Util::MapTwoUint32ToUint64(c.timeout_0, c.timeout_1);
+  typedef cmds::ClientWaitSync::Result Result;
+  Result* result_dst = GetSharedMemoryAs<Result*>(
+      c.result_shm_id, c.result_shm_offset, sizeof(*result_dst));
+  if (!result_dst) {
+    return error::kOutOfBounds;
+  }
+  if (*result_dst != GL_WAIT_FAILED) {
+    return error::kInvalidArguments;
+  }
+  GLsync service_sync = 0;
+  if (!group_->GetSyncServiceId(sync, &service_sync)) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "ClientWaitSync", "invalid sync");
+    return error::kNoError;
+  }
+  *result_dst = glClientWaitSync(service_sync, flags, timeout);
+  return error::kNoError;
+}
+
 void GLES2DecoderImpl::OnTextureRefDetachedFromFramebuffer(
     TextureRef* texture_ref) {
   Texture* texture = texture_ref->texture();