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

chrome/browser/ui/find_bar/find_bar_controller.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/find_bar/find_bar_controller.h"
 
 #include <algorithm>
 
 #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"
 #include "chrome/browser/ui/find_bar/find_bar.h"
 #include "chrome/browser/ui/find_bar/find_bar_state.h"
 #include "chrome/browser/ui/find_bar/find_bar_state_factory.h"
 #include "chrome/browser/ui/find_bar/find_tab_helper.h"
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_details.h"
@@ skipping 115 matching lines @@
   if (type == chrome::NOTIFICATION_FIND_RESULT_AVAILABLE) {
     // Don't update for notifications from WebContentses other than the one we
     // are actively tracking.
     if (content::Source<WebContents>(source).ptr() == web_contents_) {
       UpdateFindBarForCurrentResult();
       if (find_tab_helper->find_result().final_update() &&
           find_tab_helper->find_result().number_of_matches() == 0) {
         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) {
     NavigationController* source_controller =
         content::Source<NavigationController>(source).ptr();
     if (source_controller == &web_contents_->GetController()) {
       content::LoadCommittedDetails* commit_details =
           content::Details<content::LoadCommittedDetails>(details).ptr();
       ui::PageTransition transition_type =
           commit_details->entry->GetTransitionType();
@@ skipping 92 matching lines @@
   }
 
   // Update the find bar with existing results and search text, regardless of
   // whether or not the find bar is visible, so that if it's subsequently
   // shown it is showing the right state for this tab. We update the find text
   // _first_ since the FindBarView checks its emptiness to see if it should
   // clear the result count display when there's nothing in the box.
   find_bar_->SetFindTextAndSelectedRange(find_string,
                                          find_tab_helper->selected_range());
 }