Enable tooltips for aura.

content/browser/renderer_host/render_widget_host_view_aura.cc

 // Copyright (c) 2011 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 "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/logging.h"
 #include "content/browser/renderer_host/backing_store_skia.h"
 #include "content/browser/renderer_host/web_input_event_aura.h"
 #include "content/browser/renderer_host/render_widget_host.h"
@@ skipping 162 matching lines @@
                                               int error_code) {
   UpdateCursorIfOverSelf();
   Destroy();
 }
 
 void RenderWidgetHostViewAura::Destroy() {
   delete window_;
 }
 
 void RenderWidgetHostViewAura::SetTooltipText(const string16& tooltip_text) {
-  //NOTIMPLEMENTED();
+  window_->set_tooltip(tooltip_text);
 }
 
 BackingStore* RenderWidgetHostViewAura::AllocBackingStore(
     const gfx::Size& size) {
   return new BackingStoreSkia(host_, size);
 }
 
 #if defined(UI_COMPOSITOR_IMAGE_TRANSPORT)
 void RenderWidgetHostViewAura::AcceleratedSurfaceNew(
       int32 width,
@@ skipping 224 matching lines @@
 
 #if !defined(TOUCH_UI)
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewAura, private:
 
 void RenderWidgetHostViewAura::UpdateCursorIfOverSelf() {
   //NOTIMPLEMENTED();
   // TODO(beng): See RenderWidgetHostViewWin.
 }
 #endif