Remove redundant c_str() calls.

chrome/browser/font_family_cache.cc

Index: chrome/browser/font_family_cache.cc
diff --git a/chrome/browser/font_family_cache.cc b/chrome/browser/font_family_cache.cc
index 45d6a9affdefe337c41453622f9195ed48714e15..6106364eb5aa49dd5d85256a0e3639055ffe6b39 100644
--- a/chrome/browser/font_family_cache.cc
+++ b/chrome/browser/font_family_cache.cc
@@ -69,7 +69,7 @@ base::string16 FontFamilyCache::FetchFont(const char* script,
 
   // Register for profile preference changes.
   profile_pref_registrar_.Add(
-      pref_name.c_str(),
+      pref_name,
       base::Bind(&FontFamilyCache::OnPrefsChanged, base::Unretained(this)));
   return font16;
 }
@@ -122,7 +122,7 @@ void FontFamilyCache::OnPrefsChanged(const std::string& pref_name) {
 
       // Clear the cache and the observer.
       map.erase(it2);
-      profile_pref_registrar_.Remove(pref_name.c_str());
+      profile_pref_registrar_.Remove(pref_name);
       break;
     }
   }