Clarify the strings in the external protocol dialog.

chrome/browser/ui/cocoa/external_protocol_dialog.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/external_protocol_dialog.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "chrome/browser/external_protocol/external_protocol_handler.h"
 #include "chrome/browser/shell_integration.h"
@@ skipping 48 matching lines @@
 
   alert_ = [[NSAlert alloc] init];
 
   [alert_ setMessageText:
       l10n_util::GetNSStringFWithFixup(IDS_EXTERNAL_PROTOCOL_TITLE, appName)];
 
   NSButton* allowButton = [alert_
       addButtonWithTitle:l10n_util::GetNSStringFWithFixup(
                    IDS_EXTERNAL_PROTOCOL_OK_BUTTON_TEXT, appName)];
   [allowButton setKeyEquivalent:@""];  // disallow as default
-  [alert_ addButtonWithTitle:l10n_util::GetNSStringWithFixup(IDS_CANCEL)];
+  [alert_ addButtonWithTitle:
+      l10n_util::GetNSStringWithFixup(
+                   IDS_EXTERNAL_PROTOCOL_CANCEL_BUTTON_TEXT)];
 
   [alert_ setShowsSuppressionButton:YES];
   [[alert_ suppressionButton]
       setTitle:l10n_util::GetNSStringFWithFixup(
                    IDS_EXTERNAL_PROTOCOL_CHECKBOX_TEXT, appName)];
 
   [alert_ beginSheetModalForWindow:nil  // nil here makes it app-modal
                      modalDelegate:self
                     didEndSelector:@selector(alertEnded:returnCode:contextInfo:)
                        contextInfo:nil];
@@ skipping 36 matching lines @@
                              base::Time::Now() - creation_time_);
 
     ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck(
         url_, render_process_host_id_, routing_id_);
   }
 
   [self autorelease];
 }
 
 @end