cc: Pass SurfaceId by const ref in more places

cc/surfaces/surface_manager.cc

 // Copyright 2014 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 "cc/surfaces/surface_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/logging.h"
@@ skipping 33 matching lines @@
   DCHECK_EQ(registered_sources_.size(), 0u);
 }
 
 void SurfaceManager::RegisterSurface(Surface* surface) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(surface);
   DCHECK(!surface_map_.count(surface->surface_id()));
   surface_map_[surface->surface_id()] = surface;
 }
 
-void SurfaceManager::DeregisterSurface(SurfaceId surface_id) {
+void SurfaceManager::DeregisterSurface(const SurfaceId& surface_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   SurfaceMap::iterator it = surface_map_.find(surface_id);
   DCHECK(it != surface_map_.end());
   surface_map_.erase(it);
 }
 
 void SurfaceManager::Destroy(std::unique_ptr<Surface> surface) {
   DCHECK(thread_checker_.CalledOnValidThread());
   surface->set_destroyed(true);
   surfaces_to_destroy_.push_back(std::move(surface));
@@ skipping 40 matching lines @@
       live_surfaces.push_back(map_entry.first);
     }
   }
 
   // Mark all surfaces reachable from live surfaces by adding them to
   // live_surfaces and live_surfaces_set.
   for (size_t i = 0; i < live_surfaces.size(); i++) {
     Surface* surf = surface_map_[live_surfaces[i]];
     DCHECK(surf);
 
-    for (SurfaceId id : surf->referenced_surfaces()) {
+    for (const SurfaceId& id : surf->referenced_surfaces()) {
       if (live_surfaces_set.count(id))
         continue;
 
       Surface* surf2 = GetSurfaceForId(id);
       if (surf2) {
         live_surfaces.push_back(id);
         live_surfaces_set.insert(id);
       }
     }
   }
@@ skipping 198 matching lines @@
   BeginFrameSource* parent_source = iter->second.source;
   if (!parent_source)
     return;
 
   // TODO(enne): these walks could be done in one step.
   RecursivelyDetachBeginFrameSource(child_namespace, parent_source);
   for (auto source_iter : registered_sources_)
     RecursivelyAttachBeginFrameSource(source_iter.second, source_iter.first);
 }
 
-Surface* SurfaceManager::GetSurfaceForId(SurfaceId surface_id) {
+Surface* SurfaceManager::GetSurfaceForId(const SurfaceId& surface_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   SurfaceMap::iterator it = surface_map_.find(surface_id);
   if (it == surface_map_.end())
     return NULL;
   return it->second;
 }
 
-bool SurfaceManager::SurfaceModified(SurfaceId surface_id) {
+bool SurfaceManager::SurfaceModified(const SurfaceId& surface_id) {
   CHECK(thread_checker_.CalledOnValidThread());
   bool changed = false;
   FOR_EACH_OBSERVER(SurfaceDamageObserver, observer_list_,
                     OnSurfaceDamaged(surface_id, &changed));
   return changed;
 }
 
 }  // namespace cc