aura: Add flag to indicate if a drag session is started with touch or mouse.

ash/drag_drop/drag_drop_controller_unittest.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 "ash/drag_drop/drag_drop_controller.h"
 
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "base/location.h"
 #include "base/utf_string_conversions.h"
@@ skipping 111 matching lines @@
   bool drag_start_received_;
   int num_drag_updates_;
   bool drop_received_;
   bool drag_canceled_;
   string16 drag_string_;
 
  private:
   int StartDragAndDrop(const ui::OSExchangeData& data,
                        aura::RootWindow* root_window,
                        const gfx::Point& location,
-                       int operation) OVERRIDE {
+                       int operation,
+                       ui::DragDropTypes::DragEventSource source) OVERRIDE {
     drag_start_received_ = true;
     data.GetString(&drag_string_);
     return DragDropController::StartDragAndDrop(
-        data, root_window, location, operation);
+        data, root_window, location, operation, source);
   }
 
   void DragUpdate(aura::Window* target,
                   const ui::LocatedEvent& event) OVERRIDE {
     DragDropController::DragUpdate(target, event);
     num_drag_updates_++;
   }
 
   void Drop(aura::Window* target, const ui::LocatedEvent& event) OVERRIDE {
     DragDropController::Drop(target, event);
@@ skipping 523 matching lines @@
   EXPECT_EQ(1, drag_view->num_drag_enters_);
   EXPECT_EQ(num_drags - 1 - drag_view->VerticalDragThreshold(),
       drag_view->num_drag_updates_);
   EXPECT_EQ(0, drag_view->num_drops_);
   EXPECT_EQ(1, drag_view->num_drag_exits_);
   EXPECT_TRUE(drag_view->drag_done_received_);
 }
 
 }  // namespace test
 }  // namespace aura