Coverity: Pass strings by reference.

CID=2714,2715
BUG=none
TEST=none
Review URL: http://codereview.chromium.org/159351

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21566 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 7 insertions, 6 deletions

diff --git a/chrome/browser/extensions/extension_message_service.cc b/chrome/browser/extensions/extension_message_service.cc
index d4e6d0f..38e202b 100644
--- a/chrome/browser/extensions/extension_message_service.cc
+++ b/chrome/browser/extensions/extension_message_service.cc
@@ -128,7 +128,7 @@ void ExtensionMessageService::ProfileDestroyed() {
   registrar_.RemoveAll();
 }
 
-void ExtensionMessageService::AddEventListener(std::string event_name,
+void ExtensionMessageService::AddEventListener(const std::string& event_name,
                                                int render_process_id) {
   DCHECK(RenderProcessHost::FromID(render_process_id)) <<
       "Adding event listener to a non-existant RenderProcessHost.";
@@ -137,7 +137,7 @@ void ExtensionMessageService::AddEventListener(std::string event_name,
   listeners_[event_name].insert(render_process_id);
 }
 
-void ExtensionMessageService::RemoveEventListener(std::string event_name,
+void ExtensionMessageService::RemoveEventListener(const std::string& event_name,
                                                   int render_process_id) {
   // It is possible that this RenderProcessHost is being destroyed.  If that is
   // the case, we'll have already removed his listeners, so do nothing here.
diff --git a/chrome/browser/extensions/extension_message_service.h b/chrome/browser/extensions/extension_message_service.h
index 3b4e367..60e2e2b 100644
--- a/chrome/browser/extensions/extension_message_service.h
+++ b/chrome/browser/extensions/extension_message_service.h
@@ -60,15 +60,16 @@ class ExtensionMessageService :
 
   // --- UI thread only:
 
-  ExtensionMessageService(Profile* profile);
+  explicit ExtensionMessageService(Profile* profile);
   ~ExtensionMessageService();
 
   // Notification that our owning profile is going away.
   void ProfileDestroyed();
 
   // Add or remove |render_process_pid| as a listener for |event_name|.
-  void AddEventListener(std::string event_name, int render_process_id);
-  void RemoveEventListener(std::string event_name, int render_process_id);
+  void AddEventListener(const std::string& event_name, int render_process_id);
+  void RemoveEventListener(const std::string& event_name,
+                           int render_process_id);
 
   // Closes the message channel associated with the given port, and notifies
   // the other side.
@@ -104,7 +105,7 @@ class ExtensionMessageService :
   // Same as above, but opens a channel to the tab with the given ID.  Messages
   // are restricted to that tab, so if there are multiple tabs in that process,
   // only the targeted tab will receive messages.
-  int OpenChannelToTab(int routing_id, int tab_id, 
+  int OpenChannelToTab(int routing_id, int tab_id,
                        const std::string& extension_id,
                        const std::string& channel_name,
                        ResourceMessageFilter* source);