Adding UMA stats for dragdrop events for both touch and mouse.

ui/views/widget/desktop_aura/desktop_drop_target_win.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/desktop_aura/desktop_drop_target_win.h"
 
+#include "base/metrics/histogram.h"
 #include "base/win/win_util.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/drop_target_event.h"
 #include "ui/base/dragdrop/os_exchange_data_provider_win.h"
 #include "ui/events/event_constants.h"
 #include "ui/wm/public/drag_drop_client.h"
 #include "ui/wm/public/drag_drop_delegate.h"
 
+using aura::client::DragDropClient;
 using aura::client::DragDropDelegate;
 using ui::OSExchangeData;
 using ui::OSExchangeDataProviderWin;
 
 namespace views {
 
 DesktopDropTargetWin::DesktopDropTargetWin(aura::Window* root_window,
                                            HWND window)
     : ui::DropTargetWin(window),
       root_window_(root_window),
@@ skipping 38 matching lines @@
 
 DWORD DesktopDropTargetWin::OnDrop(IDataObject* data_object,
                                    DWORD key_state,
                                    POINT position,
                                    DWORD effect) {
   int drag_operation = ui::DragDropTypes::DRAG_NONE;
   scoped_ptr<OSExchangeData> data;
   scoped_ptr<ui::DropTargetEvent> event;
   DragDropDelegate* delegate;
   Translate(data_object, key_state, position, effect, &data, &event, &delegate);
-  if (delegate)
+  if (delegate) {
     drag_operation = delegate->OnPerformDrop(*event);
+    DragDropClient* client = aura::client::GetDragDropClient(root_window_);
+    if (client && !client->IsDragDropInProgress() &&
+        drag_operation != ui::DragDropTypes::DRAG_NONE) {
+      UMA_HISTOGRAM_COUNTS("DragDrop.ExternalOriginDrop", 1);
+    }
+  }
   if (target_window_) {
     target_window_->RemoveObserver(this);
     target_window_ = NULL;
   }
   return ui::DragDropTypes::DragOperationToDropEffect(drag_operation);
 }
 
 void DesktopDropTargetWin::OnWindowDestroyed(aura::Window* window) {
   DCHECK(window == target_window_);
   target_window_ = NULL;
@@ skipping 51 matching lines @@
     return;
   DragDropDelegate* delegate =
       aura::client::GetDragDropDelegate(target_window_);
   if (delegate)
     delegate->OnDragExited();
   target_window_->RemoveObserver(this);
   target_window_ = NULL;
 }
 
 }  // namespace views