aura: Make aura::TooltipClient completely static?

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/render_widget_host.h"
 #include "content/browser/renderer_host/web_input_event_aura.h"
@@ skipping 255 matching lines @@
   UpdateCursorIfOverSelf();
   Destroy();
 }
 
 void RenderWidgetHostViewAura::Destroy() {
   delete window_;
 }
 
 void RenderWidgetHostViewAura::SetTooltipText(const string16& tooltip_text) {
   tooltip_ = tooltip_text;
-  void* property = aura::Desktop::GetInstance()->GetProperty(
-      aura::kDesktopTooltipClientKey);
-  if (property) {
-    aura::TooltipClient* tc = static_cast<aura::TooltipClient*>(property);
-    tc->UpdateTooltip(window_);
-  }
+  aura::TooltipClient::UpdateTooltip(window_);
 }
 
 BackingStore* RenderWidgetHostViewAura::AllocBackingStore(
     const gfx::Size& size) {
   return new BackingStoreSkia(host_, size);
 }
 
 void RenderWidgetHostViewAura::OnAcceleratedCompositingStateChange() {
   UpdateExternalTexture();
 }
@@ skipping 320 matching lines @@
 // static
 void RenderWidgetHostView::GetDefaultScreenInfo(
     WebKit::WebScreenInfo* results) {
   const gfx::Size size = gfx::Screen::GetPrimaryMonitorSize();
   results->rect = WebKit::WebRect(0, 0, size.width(), size.height());
   results->availableRect = results->rect;
   // TODO(derat): Don't hardcode this?
   results->depth = 24;
   results->depthPerComponent = 8;
 }