[Textfield] Consider select all status for select all context menu

ui/views/controls/textfield/textfield.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 "ui/views/controls/textfield/textfield.h"
 
 #include <string>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
@@ skipping 335 matching lines @@
   return model_->GetSelectedText();
 }
 
 void Textfield::SelectAll(bool reversed) {
   model_->SelectAll(reversed);
   if (HasSelection() && performing_user_action_)
     UpdateSelectionClipboard();
   UpdateAfterChange(false, true);
 }
 
+bool Textfield::IsAllSelected() const {
+  return !text().empty() && GetSelectedText().length() == text().length();

[Peter Kasting, 2017/04/20 00:08:30]

It seems like it would be more efficient to see if GetSelectedRange() covers the
whole text range.  That wouldn't result in copying the text string just to check
its length.

[simonhong, 2017/04/20 13:11:51]

Done.

+}
+
 void Textfield::SelectWordAt(const gfx::Point& point) {
   model_->MoveCursorTo(point, false);
   model_->SelectWord();
   UpdateAfterChange(false, true);
 }
 
 void Textfield::ClearSelection() {
   model_->ClearSelection();
   UpdateAfterChange(false, true);
 }
@@ skipping 1173 matching lines @@
       return editable && model_->CanRedo();
     case ui::TextEditCommand::CUT:
       return editable && readable && model_->HasSelection();
     case ui::TextEditCommand::COPY:
       return readable && model_->HasSelection();
     case ui::TextEditCommand::PASTE:
       ui::Clipboard::GetForCurrentThread()->ReadText(
           ui::CLIPBOARD_TYPE_COPY_PASTE, &result);
       return editable && !result.empty();
     case ui::TextEditCommand::SELECT_ALL:
-      return !text().empty();
+      return !IsAllSelected();
     case ui::TextEditCommand::TRANSPOSE:
       return editable && !model_->HasSelection() &&
              !model_->HasCompositionText();
     case ui::TextEditCommand::YANK:
       return editable;
     case ui::TextEditCommand::MOVE_DOWN:
     case ui::TextEditCommand::MOVE_DOWN_AND_MODIFY_SELECTION:
     case ui::TextEditCommand::MOVE_PAGE_DOWN:
     case ui::TextEditCommand::MOVE_PAGE_DOWN_AND_MODIFY_SELECTION:
     case ui::TextEditCommand::MOVE_PAGE_UP:
@@ skipping 538 matching lines @@
   cursor_blink_timer_.Stop();
 }
 
 void Textfield::OnCursorBlinkTimerFired() {
   DCHECK(ShouldBlinkCursor());
   cursor_view_.SetVisible(!cursor_view_.visible());
   UpdateCursorViewPosition();
 }
 
 }  // namespace views