[Mac] Support undo in the omnibox.

chrome/browser/autocomplete/autocomplete_edit_view_mac.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.
 
 #include "chrome/browser/autocomplete/autocomplete_edit_view_mac.h"
 
 #include <Carbon/Carbon.h>  // kVK_Return
 
 #include "app/clipboard/clipboard.h"
 #include "app/gfx/font.h"
@@ skipping 339 matching lines @@
 void AutocompleteEditViewMac::RevertAll() {
   ClosePopup();
   model_->Revert();
 
   // TODO(shess): This should be a no-op, the results from GetText()
   // could only get there via UpdateAndStyleText() in the first place.
   // Dig into where this code can be called from and see if this line
   // can be removed.
   EmphasizeURLComponents();
   controller_->OnChanged();
+  [field_ clearUndoChain];
 }
 
 void AutocompleteEditViewMac::UpdatePopup() {
   model_->SetInputInProgress(true);
   if (!model_->has_focus())
     return;
 
   // TODO(shess):
   // Shouldn't inline autocomplete when the caret/selection isn't at
   // the end of the text.
@@ skipping 101 matching lines @@
 void AutocompleteEditViewMac::OnTemporaryTextMaybeChanged(
     const std::wstring& display_text, bool save_original_selection) {
   // TODO(shess): I believe this is for when the user arrows around
   // the popup, will be restored if they hit escape.  Figure out if
   // that is for certain it.
   if (save_original_selection)
     saved_temporary_selection_ = GetSelectedRange();
 
   SetWindowTextAndCaretPos(display_text, display_text.size());
   controller_->OnChanged();
+  [field_ clearUndoChain];
 }
 
 bool AutocompleteEditViewMac::OnInlineAutocompleteTextMaybeChanged(
     const std::wstring& display_text, size_t user_text_length) {
   // TODO(shess): Make sure that this actually works.  The round trip
   // to native form and back may mean that it's the same but not the
   // same.
   if (display_text == GetText()) {
     return false;
   }
 
   DCHECK_LE(user_text_length, display_text.size());
   const NSRange range = NSMakeRange(user_text_length, display_text.size());
   SetTextAndSelectedRange(display_text, range);
   controller_->OnChanged();
+  [field_ clearUndoChain];
 
   return true;
 }
 
 void AutocompleteEditViewMac::OnRevertTemporaryText() {
   SetSelectedRange(saved_temporary_selection_);
 }
 
 bool AutocompleteEditViewMac::IsFirstResponder() const {
   return [field_ currentEditor] != nil ? true : false;
@@ skipping 381 matching lines @@
   // TODO(shess): Figure out where the selection belongs.  On GTK,
   // it's set to the start of the text.
 }
 
 // Signal that we've lost focus when the window resigns key.
 - (void)windowDidResignKey:(NSNotification*)notification {
   edit_view_->OnDidResignKey();
 }
 
 @end