Support Drag and Drop across displays.

This CL introduces DragDropTracker, which
- Makes a dummy window capture events while dragging an item, and
- Dispatches mouse events to the window at the pointer location in DragDropController::PreHandleMouseEvent.

BUG=136817


Review URL: https://chromiumcodereview.appspot.com/10855159

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153401 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 366 insertions, 21 deletions

diff --git a/ash/drag_drop/drag_drop_controller.cc b/ash/drag_drop/drag_drop_controller.cc
index c273bf0..5d44085 100644
--- a/ash/drag_drop/drag_drop_controller.cc
+++ b/ash/drag_drop/drag_drop_controller.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -44,7 +45,6 @@ DragDropController::DragDropController()
       drag_data_(NULL),
       drag_operation_(0),
       drag_window_(NULL),
-      drag_drop_in_progress_(false),
       should_block_during_drag_drop_(true) {
   Shell::GetInstance()->AddEnvEventFilter(this);
 }
@@ -57,16 +57,13 @@ DragDropController::~DragDropController() {
 }
 
 int DragDropController::StartDragAndDrop(const ui::OSExchangeData& data,
+                                         aura::RootWindow* root_window,
                                          const gfx::Point& root_location,
                                          int operation) {
-  DCHECK(!drag_drop_in_progress_);
-  // TODO(oshima): Add CaptureClient client API.
-  aura::Window* capture_window =
-      aura::client::GetCaptureWindow(Shell::GetPrimaryRootWindow());
-  if (capture_window)
-    capture_window->ReleaseCapture();
-  drag_drop_in_progress_ = true;
+  DCHECK(!IsDragDropInProgress());
+
   drag_cursor_ = ui::kCursorPointer;
+  drag_drop_tracker_.reset(new DragDropTracker(root_window));
 
   drag_data_ = &data;
   drag_operation_ = operation;
@@ -197,7 +194,7 @@ void DragDropController::DragCancel() {
 }
 
 bool DragDropController::IsDragDropInProgress() {
-  return drag_drop_in_progress_;
+  return !!drag_drop_tracker_.get();
 }
 
 gfx::NativeCursor DragDropController::GetDragCursor() {
@@ -206,7 +203,7 @@ gfx::NativeCursor DragDropController::GetDragCursor() {
 
 bool DragDropController::PreHandleKeyEvent(aura::Window* target,
                                            ui::KeyEvent* event) {
-  if (drag_drop_in_progress_ && event->key_code() == ui::VKEY_ESCAPE) {
+  if (IsDragDropInProgress() && event->key_code() == ui::VKEY_ESCAPE) {
     DragCancel();
     return true;
   }
@@ -215,17 +212,23 @@ bool DragDropController::PreHandleKeyEvent(aura::Window* target,
 
 bool DragDropController::PreHandleMouseEvent(aura::Window* target,
                                              ui::MouseEvent* event) {
-  if (!drag_drop_in_progress_)
+  if (!IsDragDropInProgress())
     return false;
-  switch (event->type()) {
+  aura::Window* translated_target = drag_drop_tracker_->GetTarget(*event);
+  if (!translated_target) {
+    DragCancel();
+    return true;
+  }
+  scoped_ptr<ui::MouseEvent> translated_event(
+      drag_drop_tracker_->ConvertMouseEvent(translated_target, *event));
+  switch (translated_event->type()) {
     case ui::ET_MOUSE_DRAGGED:
-      DragUpdate(target, *event);
+      DragUpdate(translated_target, *translated_event.get());
       break;
     case ui::ET_MOUSE_RELEASED:
-      Drop(target, *event);
+      Drop(translated_target, *translated_event.get());
       break;
     default:
-      // We could reach here if the user drops outside the root window.
       // We could also reach here because RootWindow may sometimes generate a
       // bunch of fake mouse events
       // (aura::RootWindow::PostMouseMoveEventAfterWindowChange).
@@ -238,7 +241,9 @@ ui::TouchStatus DragDropController::PreHandleTouchEvent(
     aura::Window* target,
     ui::TouchEvent* event) {
   // TODO(sad): Also check for the touch-id.
-  if (!drag_drop_in_progress_)
+  // TODO(varunjain): Add code for supporting drag-and-drop across displays
+  // (http://crbug.com/114755).
+  if (!IsDragDropInProgress())
     return ui::TOUCH_STATUS_UNKNOWN;
   switch (event->type()) {
     case ui::ET_TOUCH_MOVED:
@@ -277,7 +282,7 @@ void DragDropController::OnImplicitAnimationsCompleted() {
 
   // By the time we finish animation, another drag/drop session may have
   // started. We do not want to destroy the drag image in that case.
-  if (!drag_drop_in_progress_)
+  if (!IsDragDropInProgress())
     drag_image_.reset();
 }
 
@@ -301,7 +306,9 @@ void DragDropController::Cleanup() {
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
-  drag_drop_in_progress_ = false;
+  // Cleanup can be called again while deleting DragDropTracker, so use Pass
+  // instead of reset to avoid double free.
+  drag_drop_tracker_.Pass();
 }
 
 }  // namespace internal
diff --git a/ash/drag_drop/drag_drop_controller.h b/ash/drag_drop/drag_drop_controller.h
index 468ba58..dabcbc1 100644
--- a/ash/drag_drop/drag_drop_controller.h
+++ b/ash/drag_drop/drag_drop_controller.h
@@ -16,6 +16,7 @@
 #include "ui/gfx/point.h"
 
 namespace aura {
+class RootWindow;
 class Window;
 }
 
@@ -31,6 +32,7 @@ class DragDropControllerTest;
 
 namespace internal {
 
+class DragDropTracker;
 class DragImageView;
 
 class ASH_EXPORT DragDropController
@@ -48,6 +50,7 @@ class ASH_EXPORT DragDropController
 
   // Overridden from aura::client::DragDropClient:
   virtual int StartDragAndDrop(const ui::OSExchangeData& data,
+                               aura::RootWindow* root_window,
                                const gfx::Point& root_location,
                                int operation) OVERRIDE;
   virtual void DragUpdate(aura::Window* target,
@@ -95,8 +98,6 @@ class ASH_EXPORT DragDropController
   aura::Window* drag_window_;
   gfx::Point drag_start_location_;
 
-  bool drag_drop_in_progress_;
-
   // Indicates whether the caller should be blocked on a drag/drop session.
   // Only be used for tests.
   bool should_block_during_drag_drop_;
@@ -104,6 +105,8 @@ class ASH_EXPORT DragDropController
   // Closure for quitting nested message loop.
   base::Closure quit_closure_;
 
+  scoped_ptr<ash::internal::DragDropTracker> drag_drop_tracker_;
+
   DISALLOW_COPY_AND_ASSIGN(DragDropController);
 };
 
diff --git a/ash/drag_drop/drag_drop_controller_unittest.cc b/ash/drag_drop/drag_drop_controller_unittest.cc
index ca6e368..7740186 100644
--- a/ash/drag_drop/drag_drop_controller_unittest.cc
+++ b/ash/drag_drop/drag_drop_controller_unittest.cc
@@ -127,11 +127,13 @@ class TestDragDropController : public internal::DragDropController {
 
  private:
   int StartDragAndDrop(const ui::OSExchangeData& data,
+                       aura::RootWindow* root_window,
                        const gfx::Point& location,
                        int operation) OVERRIDE {
     drag_start_received_ = true;
     data.GetString(&drag_string_);
-    return DragDropController::StartDragAndDrop(data, location, operation);
+    return DragDropController::StartDragAndDrop(
+        data, root_window, location, operation);
   }
 
   void DragUpdate(aura::Window* target,
diff --git a/ash/drag_drop/drag_drop_tracker.cc b/ash/drag_drop/drag_drop_tracker.cc
new file mode 100644
index 0000000..0a04d105
--- /dev/null
+++ b/ash/drag_drop/drag_drop_tracker.cc
@@ -0,0 +1,68 @@
+// 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_tracker.h"
+
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
+#include "ash/wm/coordinate_conversion.h"
+#include "ui/aura/root_window.h"
+#include "ui/base/event.h"
+#include "ui/gfx/screen.h"
+
+namespace {
+
+// Creates a window for capturing drag events.
+aura::Window* CreateCaptureWindow(aura::RootWindow* root_window) {
+  aura::Window* window = new aura::Window(NULL);
+  window->SetType(aura::client::WINDOW_TYPE_NORMAL);
+  window->Init(ui::LAYER_NOT_DRAWN);
+  window->SetParent(NULL);
+  window->SetBoundsInScreen(root_window->GetBoundsInScreen(),
+                            gfx::Screen::GetDisplayNearestWindow(root_window));
+  window->Show();
+  return window;
+}
+
+}  // namespace
+
+namespace ash {
+namespace internal {
+
+DragDropTracker::DragDropTracker(aura::RootWindow* root_window)
+    : capture_window_(CreateCaptureWindow(root_window)) {
+  capture_window_->SetCapture();
+}
+
+DragDropTracker::~DragDropTracker()  {
+  capture_window_->ReleaseCapture();
+}
+
+aura::Window* DragDropTracker::GetTarget(const ui::LocatedEvent& event) {
+  std::pair<aura::RootWindow*, gfx::Point> pair =
+      ash::wm::GetRootWindowRelativeToWindow(capture_window_.get(),
+                                             event.location());
+  return pair.first->GetEventHandlerForPoint(pair.second);
+}
+
+ui::MouseEvent* DragDropTracker::ConvertMouseEvent(
+    aura::Window* target,
+    const ui::MouseEvent& event) {
+  DCHECK(capture_window_.get());
+  std::pair<aura::RootWindow*, gfx::Point> location_pair =
+      ash::wm::GetRootWindowRelativeToWindow(capture_window_.get(),
+                                             event.location());
+  aura::Window::ConvertPointToTarget(location_pair.first, target,
+                                     &location_pair.second);
+  std::pair<aura::RootWindow*, gfx::Point> root_location_pair =
+      ash::wm::GetRootWindowRelativeToWindow(capture_window_->GetRootWindow(),
+                                             event.root_location());
+  return new ui::MouseEvent(event.type(),
+                            location_pair.second,
+                            root_location_pair.second,
+                            event.flags());
+}
+
+}  // namespace internal
+}  // namespace ash
diff --git a/ash/drag_drop/drag_drop_tracker.h b/ash/drag_drop/drag_drop_tracker.h
new file mode 100644
index 0000000..fa56ed6
--- /dev/null
+++ b/ash/drag_drop/drag_drop_tracker.h
@@ -0,0 +1,51 @@
+// 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.
+
+#ifndef ASH_DRAG_DROP_DRAG_DROP_TRACKER_H_
+#define ASH_DRAG_DROP_DRAG_DROP_TRACKER_H_
+
+#include "ash/ash_export.h"
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/base/event.h"
+
+namespace aura {
+class RootWindow;
+class Window;
+}
+
+namespace ash {
+namespace internal {
+
+// Provides functions for handling drag events inside and outside the root
+// window where drag is started. This internally sets up a capture window for
+// tracking drag events outside the root window where drag is initiated.
+// ash/wm/coordinate_conversion.h is used internally and only X11 environment
+// is supported for now.
+class ASH_EXPORT DragDropTracker {
+ public:
+  explicit DragDropTracker(aura::RootWindow* root_window);
+  ~DragDropTracker();
+
+  // Gets the target located at |event| in the coordinates of the root window
+  // given to the constructor.
+  aura::Window* GetTarget(const ui::LocatedEvent& event);
+
+  // Converts the locations of |event| in the coordinates of the root window
+  // given to the constructor to the ones in |target|'s coordinates.
+  // Caller takes ownership of the returned object.
+  ui::MouseEvent* ConvertMouseEvent(aura::Window* target,
+                                    const ui::MouseEvent& event);
+
+ private:
+  // A window for capturing drag events while dragging.
+  scoped_ptr<aura::Window> capture_window_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragDropTracker);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_DRAG_DROP_DRAG_DROP_TRACKER_H_
diff --git a/ash/drag_drop/drag_drop_tracker_unittest.cc b/ash/drag_drop/drag_drop_tracker_unittest.cc
new file mode 100644
index 0000000..ddc75ba
--- /dev/null
+++ b/ash/drag_drop/drag_drop_tracker_unittest.cc
@@ -0,0 +1,212 @@
+// 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_tracker.h"
+
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
+#include "ash/test/ash_test_base.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/aura/root_window.h"
+#include "ui/aura/test/test_windows.h"
+#include "ui/aura/window.h"
+
+namespace ash {
+namespace test {
+
+class DragDropTrackerTest : public test::AshTestBase {
+ public:
+  virtual void SetUp() OVERRIDE {
+    AshTestBase::SetUp();
+    UpdateDisplay("0+0-200x200,0+201-200x200");
+  }
+
+  static aura::Window* CreateTestWindow(const gfx::Rect& bounds,
+                                        aura::Window* parent) {
+    static int window_id = 0;
+    return aura::test::CreateTestWindowWithDelegate(
+        new aura::test::TestWindowDelegate,
+        window_id++,
+        bounds,
+        parent);
+  }
+
+  static aura::Window* GetTarget(aura::RootWindow* root_window,
+                          const gfx::Point& location) {
+    scoped_ptr<internal::DragDropTracker> tracker(
+        new internal::DragDropTracker(root_window));
+    ui::MouseEvent e(ui::ET_MOUSE_DRAGGED,
+                     location,
+                     location,
+                     ui::EF_NONE);
+    aura::Window* target = tracker->GetTarget(e);
+    return target;
+  }
+
+  static ui::MouseEvent* ConvertMouseEvent(aura::RootWindow* root_window,
+                                           aura::Window* target,
+                                           const ui::MouseEvent& event) {
+    scoped_ptr<internal::DragDropTracker> tracker(
+        new internal::DragDropTracker(root_window));
+    ui::MouseEvent* converted = tracker->ConvertMouseEvent(target, event);
+    return converted;
+  }
+};
+
+// TODO(mazda): Remove this once ash/wm/coordinate_conversion.h supports
+// non-X11 platforms.
+#if defined(USE_X11)
+#define MAYBE_GetTarget GetTarget
+#else
+#define MAYBE_GetTarget DISABLED_GetTarget
+#endif
+
+TEST_F(DragDropTrackerTest, MAYBE_GetTarget) {
+  Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
+  EXPECT_EQ(2U, root_windows.size());
+
+  aura::Window* default_container0 =
+      ash::Shell::GetContainer(root_windows[0],
+                               ash::internal::kShellWindowId_DefaultContainer);
+  EXPECT_TRUE(NULL != default_container0);
+
+  scoped_ptr<aura::Window> window0(
+      CreateTestWindow(gfx::Rect(0, 0, 100, 100), default_container0));
+  window0->Show();
+
+  aura::Window* default_container1 =
+      ash::Shell::GetContainer(root_windows[1],
+                               ash::internal::kShellWindowId_DefaultContainer);
+  EXPECT_TRUE(NULL != default_container1);
+
+  scoped_ptr<aura::Window> window1(
+      CreateTestWindow(gfx::Rect(100, 100, 100, 100), default_container1));
+  window1->Show();
+
+  // Start tracking from the RootWindow0 and check the point on RootWindow0 that
+  // |window0| covers.
+  EXPECT_EQ(window0.get(), GetTarget(root_windows[0], gfx::Point(50, 50)));
+
+  // Start tracking from the RootWindow0 and check the point on RootWindow0 that
+  // neither |window0| nor |window1| covers.
+  EXPECT_NE(window0.get(), GetTarget(root_windows[0], gfx::Point(150, 150)));
+  EXPECT_NE(window1.get(), GetTarget(root_windows[0], gfx::Point(150, 150)));
+
+  // Start tracking from the RootWindow0 and check the point on RootWindow1 that
+  // |window1| covers.
+  EXPECT_EQ(window1.get(), GetTarget(root_windows[0], gfx::Point(150, 350)));
+
+  // Start tracking from the RootWindow0 and check the point on RootWindow1 that
+  // neither |window0| nor |window1| covers.
+  EXPECT_NE(window0.get(), GetTarget(root_windows[0], gfx::Point(50, 250)));
+  EXPECT_NE(window1.get(), GetTarget(root_windows[0], gfx::Point(50, 250)));
+
+  // Start tracking from the RootWindow1 and check the point on RootWindow0 that
+  // |window0| covers.
+  EXPECT_EQ(window0.get(), GetTarget(root_windows[1], gfx::Point(50, -150)));
+
+  // Start tracking from the RootWindow1 and check the point on RootWindow0 that
+  // neither |window0| nor |window1| covers.
+  EXPECT_NE(window0.get(), GetTarget(root_windows[1], gfx::Point(150, -50)));
+  EXPECT_NE(window1.get(), GetTarget(root_windows[1], gfx::Point(150, -50)));
+
+  // Start tracking from the RootWindow1 and check the point on RootWindow1 that
+  // |window1| covers.
+  EXPECT_EQ(window1.get(), GetTarget(root_windows[1], gfx::Point(150, 150)));
+
+  // Start tracking from the RootWindow1 and check the point on RootWindow1 that
+  // neither |window0| nor |window1| covers.
+  EXPECT_NE(window0.get(), GetTarget(root_windows[1], gfx::Point(50, 50)));
+  EXPECT_NE(window1.get(), GetTarget(root_windows[1], gfx::Point(50, 50)));
+}
+
+// TODO(mazda): Remove this once ash/wm/coordinate_conversion.h supports
+// non-X11 platforms.
+#if defined(USE_X11)
+#define MAYBE_ConvertMouseEvent ConvertMouseEvent
+#else
+#define MAYBE_ConvertMouseEvent DISABLED_ConvertMouseEvent
+#endif
+
+TEST_F(DragDropTrackerTest, MAYBE_ConvertMouseEvent) {
+  Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
+  EXPECT_EQ(2U, root_windows.size());
+
+  aura::Window* default_container0 =
+      ash::Shell::GetContainer(root_windows[0],
+                               ash::internal::kShellWindowId_DefaultContainer);
+  EXPECT_TRUE(NULL != default_container0);
+
+  scoped_ptr<aura::Window> window0(
+      CreateTestWindow(gfx::Rect(0, 0, 100, 100), default_container0));
+  window0->Show();
+
+  aura::Window* default_container1 =
+      ash::Shell::GetContainer(root_windows[1],
+                               ash::internal::kShellWindowId_DefaultContainer);
+  EXPECT_TRUE(NULL != default_container1);
+
+  scoped_ptr<aura::Window> window1(
+      CreateTestWindow(gfx::Rect(100, 100, 100, 100), default_container1));
+  window1->Show();
+
+  // Start tracking from the RootWindow0 and converts the mouse event into
+  // |window0|'s coodinates.
+  ui::MouseEvent original00(ui::ET_MOUSE_DRAGGED,
+                            gfx::Point(50, 50),
+                            gfx::Point(50, 50),
+                            ui::EF_NONE);
+  scoped_ptr<ui::MouseEvent> converted00(ConvertMouseEvent(root_windows[0],
+                                                           window0.get(),
+                                                           original00));
+  EXPECT_EQ(original00.type(), converted00->type());
+  EXPECT_EQ(gfx::Point(50, 50), converted00->location());
+  EXPECT_EQ(gfx::Point(50, 50), converted00->root_location());
+  EXPECT_EQ(original00.flags(), converted00->flags());
+
+  // Start tracking from the RootWindow0 and converts the mouse event into
+  // |window1|'s coodinates.
+  ui::MouseEvent original01(ui::ET_MOUSE_DRAGGED,
+                            gfx::Point(150, 350),
+                            gfx::Point(150, 350),
+                            ui::EF_NONE);
+  scoped_ptr<ui::MouseEvent> converted01(ConvertMouseEvent(root_windows[0],
+                                                           window1.get(),
+                                                           original01));
+  EXPECT_EQ(original01.type(), converted01->type());
+  EXPECT_EQ(gfx::Point(50, 50), converted01->location());
+  EXPECT_EQ(gfx::Point(150, 150), converted01->root_location());
+  EXPECT_EQ(original01.flags(), converted01->flags());
+
+  // Start tracking from the RootWindow1 and converts the mouse event into
+  // |window0|'s coodinates.
+  ui::MouseEvent original10(ui::ET_MOUSE_DRAGGED,
+                            gfx::Point(50, -150),
+                            gfx::Point(50, -150),
+                            ui::EF_NONE);
+  scoped_ptr<ui::MouseEvent> converted10(ConvertMouseEvent(root_windows[1],
+                                                           window0.get(),
+                                                           original10));
+  EXPECT_EQ(original10.type(), converted10->type());
+  EXPECT_EQ(gfx::Point(50, 50), converted10->location());
+  EXPECT_EQ(gfx::Point(50, 50), converted10->root_location());
+  EXPECT_EQ(original10.flags(), converted10->flags());
+
+  // Start tracking from the RootWindow1 and converts the mouse event into
+  // |window1|'s coodinates.
+  ui::MouseEvent original11(ui::ET_MOUSE_DRAGGED,
+                            gfx::Point(150, 150),
+                            gfx::Point(150, 150),
+                            ui::EF_NONE);
+  scoped_ptr<ui::MouseEvent> converted11(ConvertMouseEvent(root_windows[1],
+                                                           window1.get(),
+                                                           original11));
+  EXPECT_EQ(original11.type(), converted11->type());
+  EXPECT_EQ(gfx::Point(50, 50), converted11->location());
+  EXPECT_EQ(gfx::Point(150, 150), converted11->root_location());
+  EXPECT_EQ(original11.flags(), converted11->flags());
+}
+
+}  // namespace test
+}  // namespace aura
diff --git a/ash/drag_drop/drag_image_view.cc b/ash/drag_drop/drag_image_view.cc
index 7a138f3..b6a32f8 100644
--- a/ash/drag_drop/drag_image_view.cc
+++ b/ash/drag_drop/drag_image_view.cc
@@ -5,6 +5,7 @@
 #include "ash/drag_drop/drag_image_view.h"
 
 #include "ash/wm/shadow_types.h"
+#include "ui/aura/window.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
@@ -23,6 +24,7 @@ Widget* CreateDragWidget() {
   params.transparent = true;
   drag_widget->Init(params);
   drag_widget->SetOpacity(0xFF);
+  drag_widget->GetNativeWindow()->set_owned_by_parent(false);
   SetShadowType(drag_widget->GetNativeView(), SHADOW_TYPE_NONE);
   return drag_widget;
 }