Coverity: Fix pass by value errors in HostZoomMap::SetZoomLevel() function.

CID=103250
BUG=none
TEST=none


Review URL: https://chromiumcodereview.appspot.com/10377144

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137230 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/host_zoom_map_impl.cc

@@ -71,7 +71,7 @@ double HostZoomMapImpl::GetZoomLevel(const std::string& host) const {
   return (i == host_zoom_levels_.end()) ? default_zoom_level_ : i->second;
 }
 
-void HostZoomMapImpl::SetZoomLevel(std::string host, double level) {
+void HostZoomMapImpl::SetZoomLevel(const std::string& host, double level) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   {

content/browser/host_zoom_map_impl.h

@@ -31,7 +31,7 @@ class CONTENT_EXPORT HostZoomMapImpl
   // HostZoomMap implementation:
   virtual void CopyFrom(HostZoomMap* copy) OVERRIDE;
   virtual double GetZoomLevel(const std::string& host) const OVERRIDE;
-  virtual void SetZoomLevel(std::string host, double level) OVERRIDE;
+  virtual void SetZoomLevel(const std::string& host, double level) OVERRIDE;
   virtual double GetDefaultZoomLevel() const OVERRIDE;
   virtual void SetDefaultZoomLevel(double level) OVERRIDE;
 

content/public/browser/host_zoom_map.h

@@ -45,7 +45,7 @@ class HostZoomMap {
   // from the saved preferences; otherwise the new value is written out.
   //
   // This should only be called on the UI thread.
-  virtual void SetZoomLevel(std::string host, double level) = 0;
+  virtual void SetZoomLevel(const std::string& host, double level) = 0;
 
   // Get/Set the default zoom level for pages that don't override it.
   virtual double GetDefaultZoomLevel() const = 0;