Aura: notify DropHelper when target view is removed.

ui/views/widget/native_widget_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 "ui/views/widget/native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/string_util.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/drag_drop_client.h"
@@ skipping 217 matching lines @@
     gfx::Point* offset,
     ui::Layer** layer_parent) {
   if (layer_parent)
     *layer_parent = window_->layer();
 }
 
 void NativeWidgetAura::ReorderLayers() {
 }
 
 void NativeWidgetAura::ViewRemoved(View* view) {
-  // DropTarget stuff. Most likely http://crbug.com/97845
-  //NOTIMPLEMENTED();
+  DCHECK(drop_helper_.get() != NULL);
+  drop_helper_->ResetTargetViewIfEquals(view);
 }
 
 void NativeWidgetAura::SetNativeWindowProperty(const char* name, void* value) {
   if (window_)
     window_->SetProperty(name, value);
 }
 
 void* NativeWidgetAura::GetNativeWindowProperty(const char* name) const {
   return window_ ? window_->GetProperty(name) : NULL;
 }
@@ skipping 529 matching lines @@
   NOTIMPLEMENTED();
 }
 
 // static
 bool NativeWidgetPrivate::IsMouseButtonDown() {
   return aura::Desktop::GetInstance()->IsMouseButtonDown();
 }
 
 }  // namespace internal
 }  // namespace views