[Mac] Force-enable the find next/previous buttons when pressing...

chrome/browser/cocoa/find_bar_cocoa_controller.mm

 // Copyright (c) 2009 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 <Cocoa/Cocoa.h>
 
 #include "app/l10n_util.h"
 #include "base/mac_util.h"
 #include "base/sys_string_conversions.h"
 #include "grit/generated_resources.h"
@@ skipping 110 matching lines @@
 - (void)showFindBar {
   [[self view] setHidden:NO];
 }
 
 - (void)hideFindBar {
   [[self view] setHidden:YES];
 }
 
 - (void)setFocusAndSelection {
   [[findText_ window] makeFirstResponder:findText_];
+
+  // Enable the buttons if the find text is non-empty.
+  BOOL buttonsEnabled = ([[findText_ stringValue] length] > 0) ? YES : NO;
+  [previousButton_ setEnabled:buttonsEnabled];
+  [nextButton_ setEnabled:buttonsEnabled];
+
 }
 
 - (void)setFindText:(const string16&)findText {
   [findText_ setStringValue:base::SysUTF16ToNSString(findText)];
 }
 
 - (void)clearResults:(const FindNotificationDetails&)results {
   // Just call updateUIForFindResult, which will take care of clearing
   // the search text and the results label.
   [self updateUIForFindResult:results withText:string16()];
@@ skipping 41 matching lines @@
 
   // TODO(rohitrao): If the search string is too long, then it will overlap with
   // the results label.  Fix.
 }
 
 - (BOOL)isFindBarVisible {
   return [[self view] isHidden] ? NO : YES;
 }
 
 @end