Reland of place string::find(prefix) == 0 pattern with base::StartsWith().

chrome/browser/ui/find_bar/find_bar_controller.cc

Index: chrome/browser/ui/find_bar/find_bar_controller.cc
diff --git a/chrome/browser/ui/find_bar/find_bar_controller.cc b/chrome/browser/ui/find_bar/find_bar_controller.cc
index 909749f2437a3f06cc3c1bfaafb13c7f9ef92713..f30cf920bc94356e5d95cbec12a3ae878cd53c22 100644
--- a/chrome/browser/ui/find_bar/find_bar_controller.cc
+++ b/chrome/browser/ui/find_bar/find_bar_controller.cc
@@ -8,6 +8,7 @@
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
+#include "base/strings/string_util.h"
 #include "build/build_config.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile.h"
@@ -143,8 +144,10 @@
         const base::string16& last_search =
             find_tab_helper->previous_find_text();
         const base::string16& current_search = find_tab_helper->find_text();
-        if (last_search.find(current_search) != 0)
+        if (base::StartsWith(last_search, current_search,
+                             base::CompareCase::SENSITIVE)) {
           find_bar_->AudibleAlert();
+        }
       }
     }
   } else if (type == content::NOTIFICATION_NAV_ENTRY_COMMITTED) {