Improve WorkspaceWindowResizer::CompleteDrag() so that the function moves the window to a root windo

ash/wm/workspace/workspace_window_resizer.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/wm/workspace/workspace_window_resizer.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "ash/display/display_controller.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/wm/coordinate_conversion.h"
 #include "ash/wm/cursor_manager.h"
 #include "ash/wm/property_util.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace/phantom_window_controller.h"
 #include "ash/wm/workspace/snap_sizer.h"
 #include "ui/aura/client/aura_constants.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/hit_test.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/transform.h"
 
 namespace ash {
@@ skipping 53 matching lines @@
 }
 
 void WorkspaceWindowResizer::Drag(const gfx::Point& location, int event_flags) {
   std::pair<aura::RootWindow*, gfx::Point> actual_location =
       wm::GetRootWindowRelativeToWindow(window()->parent(), location);
   aura::RootWindow* current_root = actual_location.first;
   gfx::Point location_in_parent = actual_location.second;
   aura::Window::ConvertPointToTarget(current_root,
                                      window()->parent(),
                                      &location_in_parent);
+  last_mouse_location_ = location_in_parent;
 
   // Do not use |location| below this point, use |location_in_parent| instead.
   // When the pointer is on |window()->GetRootWindow()|, |location| and
   // |location_in_parent| have the same value and both of them are in
   // |window()->parent()|'s coordinates, but once the pointer enters the
   // other root window, you will see an unexpected value on the former. See
   // comments in wm::GetRootWindowRelativeToWindow() for details.
 
   int grid_size = event_flags & ui::EF_CONTROL_DOWN ?
                   0 : ash::Shell::GetInstance()->GetGridSize();
@@ skipping 36 matching lines @@
 
   if (snap_type_ == SNAP_LEFT_EDGE || snap_type_ == SNAP_RIGHT_EDGE) {
     if (!GetRestoreBoundsInScreen(details_.window))
       SetRestoreBoundsInParent(details_.window, details_.initial_bounds);
     details_.window->SetBounds(snap_sizer_->target_bounds());
     return;
   }
 
   int grid_size = event_flags & ui::EF_CONTROL_DOWN ?
                   0 : ash::Shell::GetInstance()->GetGridSize();
-  if (grid_size <= 1)
+  gfx::Rect bounds(GetFinalBounds(details_.window->bounds(), grid_size));
+
+  // Check if the destination is another display.
+  gfx::Point last_mouse_location_in_screen = last_mouse_location_;
+  wm::ConvertPointToScreen(window()->parent(), &last_mouse_location_in_screen);
+  const gfx::Display dst_display =
+      gfx::Screen::GetDisplayNearestPoint(last_mouse_location_in_screen);
+
+  if (dst_display.id() !=
+      gfx::Screen::GetDisplayNearestWindow(window()->GetRootWindow()).id()) {
+    // Don't animate when moving to another display.
+    const gfx::Rect dst_bounds =
+        ScreenAsh::ConvertRectToScreen(details_.window->parent(), bounds);
+    details_.window->SetBoundsInScreen(dst_bounds, dst_display);
     return;
+  }
 
-  gfx::Rect bounds(GetFinalBounds(details_.window->bounds(), grid_size));
-  if (bounds == details_.window->bounds())
+  if (grid_size <= 1 || bounds == details_.window->bounds())
     return;
 
   if (bounds.size() != details_.window->bounds().size()) {
     // Don't attempt to animate a size change.
     details_.window->SetBounds(bounds);
     return;
   }
-  // TODO(oshima|yusukes): This is temporary solution until better drag & move
-  // is implemented. (crbug.com/136816).
-  gfx::Rect dst_bounds =
-      ScreenAsh::ConvertRectToScreen(details_.window->parent(), bounds);
-  gfx::Display dst_display = gfx::Screen::GetDisplayMatching(dst_bounds);
-  if (dst_display.id() !=
-      gfx::Screen::GetDisplayNearestWindow(details_.window).id()) {
-    // Don't animate when moving to another display.
-    details_.window->SetBoundsInScreen(dst_bounds);
-  } else {
-    ui::ScopedLayerAnimationSettings scoped_setter(
-        details_.window->layer()->GetAnimator());
-    // Use a small duration since the grid is small.
-    scoped_setter.SetTransitionDuration(
-        base::TimeDelta::FromMilliseconds(kSnapDurationMS));
-    details_.window->SetBounds(bounds);
-  }
+
+  ui::ScopedLayerAnimationSettings scoped_setter(
+      details_.window->layer()->GetAnimator());
+  // Use a small duration since the grid is small.
+  scoped_setter.SetTransitionDuration(
+      base::TimeDelta::FromMilliseconds(kSnapDurationMS));
+  details_.window->SetBounds(bounds);
 }
 
 void WorkspaceWindowResizer::RevertDrag() {
   drag_phantom_window_controller_.reset();
   snap_phantom_window_controller_.reset();
 
   if (!did_move_or_resize_)
     return;
 
   details_.window->SetBounds(details_.initial_bounds);
@@ skipping 349 matching lines @@
 }
 
 bool WorkspaceWindowResizer::ShouldAllowMouseWarp() const {
   return (details_.window_component == HTCAPTION) &&
       (window()->GetProperty(aura::client::kModalKey) == ui::MODAL_TYPE_NONE) &&
       (window()->type() == aura::client::WINDOW_TYPE_NORMAL);
 }
 
 }  // namespace internal
 }  // namespace ash