[omnibox] Constrain 'IsSelectAll()' to be more accurate

chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.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.
 
 #include "chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.h"
 
 #include <Carbon/Carbon.h>  // kVK_Return
 
 #include "base/auto_reset.h"
 #include "base/mac/foundation_util.h"
@@ skipping 351 matching lines @@
 
   // Transition the user into keyword mode using their default search provider.
   model()->EnterKeywordModeForDefaultSearchProvider(
       KeywordModeEntryMethod::KEYBOARD_SHORTCUT);
 }
 
 bool OmniboxViewMac::IsSelectAll() const {
   if (![field_ currentEditor])
     return true;
   const NSRange all_range = NSMakeRange(0, GetTextLength());
+  if (all_range.length == 0)
+    return false;
   return NSEqualRanges(all_range, GetSelectedRange());
 }
 
 bool OmniboxViewMac::DeleteAtEndPressed() {
   return delete_at_end_pressed_;
 }
 
 void OmniboxViewMac::GetSelectionBounds(base::string16::size_type* start,
                                         base::string16::size_type* end) const {
   if (![field_ currentEditor]) {
@@ skipping 705 matching lines @@
                               display_text);
   NSDictionary* notification_info = @{
       NSAccessibilityAnnouncementKey : announcement,
       NSAccessibilityPriorityKey :     @(NSAccessibilityPriorityHigh)
   };
   NSAccessibilityPostNotificationWithUserInfo(
       [field_ window],
       NSAccessibilityAnnouncementRequestedNotification,
       notification_info);
 }