Cancel drag upon screen lock

ash/drag_drop/drag_drop_controller.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/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
 #include "ash/shell.h"
 #include "ash/wm/coordinate_conversion.h"
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/drag_drop_delegate.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
+#include "ui/aura/window_delegate.h"
 #include "ui/base/animation/linear_animation.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/events/event.h"
 #include "ui/base/events/event_utils.h"
+#include "ui/base/hit_test.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/views/views_delegate.h"
 #include "ui/views/widget/native_widget_aura.h"
 
 namespace ash {
 namespace internal {
 
 using aura::RootWindow;
@@ skipping 36 matching lines @@
         0,
         0,
         ui::EventTimeForNow(),
         ui::GestureEventDetails(ui::ET_GESTURE_END, 0, 0),
         0);
     window->delegate()->OnGestureEvent(&gesture_end);
   }
 }
 }  // namespace
 
+class DragDropWindowDelegate : public aura::WindowDelegate {

[varunjain, 2013/03/25 18:04:23]

nit: rename to DragDropTrackerDelegate or DragDropTrackerWindowDelegate

[oshima, 2013/03/25 20:41:10]

Done.

+ public:
+  explicit DragDropWindowDelegate(DragDropController* controller)
+      : drag_drop_controller_(controller) {}
+  virtual ~DragDropWindowDelegate() {}
+
+  // Overridden from WindowDelegate:
+  virtual gfx::Size GetMinimumSize() const OVERRIDE {
+    return gfx::Size();
+  }
+
+  virtual gfx::Size GetMaximumSize() const OVERRIDE {
+    return gfx::Size();
+  }
+
+  virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
+                               const gfx::Rect& new_bounds) OVERRIDE {}
+  virtual gfx::NativeCursor GetCursor(const gfx::Point& point) OVERRIDE {
+    return gfx::kNullCursor;
+  }
+  virtual int GetNonClientComponent(const gfx::Point& point) const OVERRIDE {
+    return HTCAPTION;
+  }
+  virtual bool ShouldDescendIntoChildForEventHandling(
+      aura::Window* child,
+      const gfx::Point& location) OVERRIDE {
+    return true;
+  }
+  virtual bool CanFocus() OVERRIDE { return true; }
+  virtual void OnCaptureLost() OVERRIDE {
+    drag_drop_controller_->DragCancel();
+  }
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
+  }
+  virtual void OnDeviceScaleFactorChanged(float device_scale_factor) OVERRIDE {}
+  virtual void OnWindowDestroying() OVERRIDE {}
+  virtual void OnWindowDestroyed() OVERRIDE {}
+  virtual void OnWindowTargetVisibilityChanged(bool visible) OVERRIDE {}
+  virtual bool HasHitTestMask() const OVERRIDE { return false; }
+  virtual void GetHitTestMask(gfx::Path* mask) const OVERRIDE {}
+  virtual scoped_refptr<ui::Texture> CopyTexture() OVERRIDE {
+    return scoped_refptr<ui::Texture>();
+  }
+
+ private:
+  DragDropController* drag_drop_controller_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragDropWindowDelegate);
+};
+
 ////////////////////////////////////////////////////////////////////////////////
 // DragDropController, public:
 
 DragDropController::DragDropController()
     : drag_image_(NULL),
       drag_data_(NULL),
       drag_operation_(0),
       drag_window_(NULL),
       drag_source_window_(NULL),
       should_block_during_drag_drop_(true),
+      ALLOW_THIS_IN_INITIALIZER_LIST(
+          drag_drop_window_delegate_(new DragDropWindowDelegate(this))),
       current_drag_event_source_(ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE),
       weak_factory_(this) {
   Shell::GetInstance()->AddPreTargetHandler(this);
 }
 
 DragDropController::~DragDropController() {
   Shell::GetInstance()->RemovePreTargetHandler(this);
   Cleanup();
   if (cancel_animation_.get())
     cancel_animation_->End();
@@ skipping 11 matching lines @@
   if (IsDragDropInProgress())
     return 0;
 
   const ui::OSExchangeData::Provider* provider = &data.provider();
   // We do not support touch drag/drop without a drag image.
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH &&
       provider->GetDragImage().size().IsEmpty())
     return 0;
 
   current_drag_event_source_ = source;
-  DragDropTracker* tracker = new DragDropTracker(root_window);
+  DragDropTracker* tracker =
+      new DragDropTracker(root_window, drag_drop_window_delegate_.get());
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
     // We need to transfer the current gesture sequence and the GR's touch event
     // queue to the |drag_drop_tracker_|'s capture window so that when it takes
     // capture, it still gets a valid gesture state.
     root_window->gesture_recognizer()->TransferEventsTo(source_window,
         tracker->capture_window());
     // We also send a gesture end to the source window so it can clear state.
     // TODO(varunjain): Remove this whole block when gesture sequence
     // transferring is properly done in the GR (http://crbug.com/160558)
     DispatchGestureEndToWindow(source_window);
@@ skipping 131 matching lines @@
   } else {
     drag_image_.reset();
   }
 
   Cleanup();
   if (should_block_during_drag_drop_)
     quit_closure_.Run();
 }
 
 void DragDropController::DragCancel() {
+  // Ignore if the drag window is already deleted. This happens when

[varunjain, 2013/03/25 18:04:23]

Can we handle this case in DragDropWindowDelegate::OnWindowDestrying?

[oshima, 2013/03/25 20:41:10]

Checking if drag&drop is in progress in OnCaptureLost seems to work.
How does this look to you?

+  // |drag_drop_tracker_| is reset, which invokes OnCaptureLost.
+  if (!drag_window_)
+    return;
   DoDragCancel(kCancelAnimationDuration);
 }
 
 bool DragDropController::IsDragDropInProgress() {
   return !!drag_drop_tracker_.get();
 }
 
 void DragDropController::OnKeyEvent(ui::KeyEvent* event) {
   if (IsDragDropInProgress() && event->key_code() == ui::VKEY_ESCAPE) {
     DragCancel();
@@ skipping 211 matching lines @@
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   // Cleanup can be called again while deleting DragDropTracker, so use Pass
   // instead of reset to avoid double free.
   drag_drop_tracker_.Pass();
 }
 
 }  // namespace internal
 }  // namespace ash