First shot at implementing drag&drop for Aura

ui/aura/desktop.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/aura/desktop.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
 #include "base/string_split.h"
 #include "ui/aura/aura_switches.h"
+#include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/client/stacking_client.h"
 #include "ui/aura/desktop_host.h"
 #include "ui/aura/desktop_observer.h"
 #include "ui/aura/event.h"
 #include "ui/aura/event_filter.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/screen_aura.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/base/hit_test.h"
@@ skipping 162 matching lines @@
 // static
 void Desktop::DeleteInstanceForTesting() {
   delete instance_;
   instance_ = NULL;
 }
 
 void Desktop::SetStackingClient(StackingClient* stacking_client) {
   stacking_client_.reset(stacking_client);
 }
 
+void Desktop::SetDragDropClient(DragDropClient* drag_drop_client) {
+  drag_drop_client_.reset(drag_drop_client);
+}
+
 void Desktop::ShowDesktop() {
   host_->Show();
 }
 
 void Desktop::SetHostSize(const gfx::Size& size) {
   host_->SetSize(size);
   // Requery the location to constrain it within the new desktop size.
   last_mouse_location_ = host_->QueryMouseLocation();
 }
 
@@ skipping 195 matching lines @@
   capture_window_ = window;
 
   if (capture_window_) {
     // Make all subsequent mouse events and touch go to the capture window. We
     // shouldn't need to send an event here as OnCaptureLost should take care of
     // that.
     if (mouse_pressed_handler_)
       mouse_pressed_handler_ = capture_window_;
     if (touch_event_handler_)
       touch_event_handler_ = capture_window_;
+  } else {
+    // When capture is lost, we must reset the event handlers.
+    mouse_pressed_handler_ = NULL;
+    touch_event_handler_ = NULL;
   }
 }
 
 void Desktop::ReleaseCapture(Window* window) {
   if (capture_window_ != window)
     return;
   SetCapture(NULL);
 }
 
 void Desktop::SetTransform(const ui::Transform& transform) {
@@ skipping 164 matching lines @@
       base::StringToInt(parts[1], &parsed_height) && parsed_height > 0) {
     bounds.set_size(gfx::Size(parsed_width, parsed_height));
   } else if (use_fullscreen_host_window_) {
     bounds = gfx::Rect(DesktopHost::GetNativeDisplaySize());
   }
 
   return bounds;
 }
 
 }  // namespace aura