Cleanup: Pass std::string as const reference from content/

content/common/gpu/gpu_channel_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/gpu/gpu_channel_manager.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 225 matching lines @@
 
 void GpuChannelManager::OnUpdateValueState(
     int client_id, unsigned int target, const gpu::ValueState& state) {
   // Only pass updated state to the channel corresponding to the
   // render_widget_host where the event originated.
   auto it = gpu_channels_.find(client_id);
   if (it != gpu_channels_.end())
     it->second->HandleUpdateValueState(target, state);
 }
 
-void GpuChannelManager::OnLoadedShader(std::string program_proto) {
+void GpuChannelManager::OnLoadedShader(const std::string& program_proto) {
   if (program_cache())
     program_cache()->LoadProgram(program_proto);
 }
 
 uint32_t GpuChannelManager::GetUnprocessedOrderNum() const {
   uint32_t unprocessed_order_num = 0;
   for (auto& kv : gpu_channels_) {
     unprocessed_order_num =
         std::max(unprocessed_order_num, kv.second->GetUnprocessedOrderNum());
   }
@@ skipping 24 matching lines @@
 
 gfx::GLSurface* GpuChannelManager::GetDefaultOffscreenSurface() {
   if (!default_offscreen_surface_.get()) {
     default_offscreen_surface_ =
         gfx::GLSurface::CreateOffscreenGLSurface(gfx::Size());
   }
   return default_offscreen_surface_.get();
 }
 
 }  // namespace content