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/desktop_delegate.h"
 #include "ui/aura/desktop_host.h"
 #include "ui/aura/desktop_observer.h"
+#include "ui/aura/drag_drop_controller.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/screen_rotation.h"
 #include "ui/aura/toplevel_window_container.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/gfx/compositor/compositor.h"
 #include "ui/gfx/compositor/layer.h"
@@ skipping 45 matching lines @@
     for (i = desktop_->children().rbegin();
          i != desktop_->children().rend();
          ++i) {
       if (*i == ignore)
         continue;
       return *i;
     }
     return NULL;
   }
 
+  virtual DragDropController* GetDragDropController() const OVERRIDE {
+    return NULL;
+  }
+
   Desktop* desktop_;
 
   DISALLOW_COPY_AND_ASSIGN(DefaultDesktopDelegate);
 };
 
 class DesktopEventFilter : public EventFilter {
  public:
   explicit DesktopEventFilter(Window* owner) : EventFilter(owner) {}
   virtual ~DesktopEventFilter() {}
 
@@ skipping 119 matching lines @@
       ALLOW_THIS_IN_INITIALIZER_LIST(
           delegate_(new DefaultDesktopDelegate(this))),
       ALLOW_THIS_IN_INITIALIZER_LIST(schedule_paint_factory_(this)),
       active_window_(NULL),
       in_destructor_(false),
       screen_(new ScreenAura),
       capture_window_(NULL),
       mouse_pressed_handler_(NULL),
       mouse_moved_handler_(NULL),
       focused_window_(NULL),
-      touch_event_handler_(NULL) {
+      touch_event_handler_(NULL),
+      drag_drop_in_progress_(false) {
   set_name("RootWindow");
   gfx::Screen::SetInstance(screen_);
   host_->SetDesktop(this);
   last_mouse_location_ = host_->QueryMouseLocation();
   SetEventFilter(new DesktopEventFilter(this));
 
   if (ui::Compositor::compositor_factory()) {
     compositor_ = (*ui::Compositor::compositor_factory())(this);
   } else {
     compositor_ = ui::Compositor::Create(this, host_->GetAcceleratedWidget(),
@@ skipping 54 matching lines @@
 
 void Desktop::Draw() {
   compositor_->Draw(false);
 }
 
 bool Desktop::DispatchMouseEvent(MouseEvent* event) {
   event->UpdateForTransform(layer()->transform());
 
   last_mouse_location_ = event->location();
 
+  if (drag_drop_in_progress_) {
+    DCHECK(delegate_->GetDragDropController());
+    switch (event->type()) {
+      case ui::ET_MOUSE_DRAGGED:
+        delegate_->GetDragDropController()->DragUpdate(*event);
+        break;
+      case ui::ET_MOUSE_RELEASED:
+        delegate_->GetDragDropController()->Drop(*event);
+      case ui::ET_MOUSE_EXITED:
+        drag_drop_in_progress_ = false;
+        MessageLoop::current()->Quit();
+        break;
+      default:
+        NOTREACHED();
+        break;
+    }
+    return true;
+  }
+
   Window* target =
       mouse_pressed_handler_ ? mouse_pressed_handler_ : capture_window_;
   if (!target)
     target = GetEventHandlerForPoint(event->location());
   switch (event->type()) {
     case ui::ET_MOUSE_MOVED:
       HandleMouseMoved(*event, target);
       break;
     case ui::ET_MOUSE_PRESSED:
       if (!mouse_pressed_handler_)
@@ skipping 177 matching lines @@
 
 void Desktop::SetTransform(const ui::Transform& transform) {
   Window::SetTransform(transform);
 
   // If the layer is not animating, then we need to update the host size
   // immediately.
   if (!layer()->GetAnimator()->is_animating())
     OnHostResized(host_->GetSize());
 }
 
+void Desktop::StartDragAndDrop(const ui::OSExchangeData& data, int operation) {
+  if (delegate_->GetDragDropController() && !drag_drop_in_progress_) {
+    if (capture_window_)
+      ReleaseCapture(capture_window_);
+    delegate_->GetDragDropController()->StartDragAndDrop(data, operation,
+        last_mouse_location_);
+    drag_drop_in_progress_ = true;
+    MessageLoopForUI::current()->RunWithDispatcher(host_.get());
+  }
+}
+
 void Desktop::HandleMouseMoved(const MouseEvent& event, Window* target) {
   if (target == mouse_moved_handler_)
     return;
 
   // Send an exited event.
   if (mouse_moved_handler_ && mouse_moved_handler_->delegate()) {
     MouseEvent translated_event(event, this, mouse_moved_handler_,
                                 ui::ET_MOUSE_EXITED);
     ProcessMouseEvent(mouse_moved_handler_, &translated_event);
   }
@@ skipping 126 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