Allow the cursor to warp even when a window is dragged

ash/wm/workspace/workspace_window_resizer.cc

Index: ash/wm/workspace/workspace_window_resizer.cc
diff --git a/ash/wm/workspace/workspace_window_resizer.cc b/ash/wm/workspace/workspace_window_resizer.cc
index a6834654de388b8ab6f81776d5c6cb01c1966641..cb96552447ef976fc9764f44ffa448f25f07ebf4 100644
--- a/ash/wm/workspace/workspace_window_resizer.cc
+++ b/ash/wm/workspace/workspace_window_resizer.cc
@@ -7,16 +7,21 @@
 #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/client/screen_position_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
+#include "ui/aura/root_window.h"
 #include "ui/base/hit_test.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
@@ -46,7 +51,10 @@ const int WorkspaceWindowResizer::kMinOnscreenSize = 20;
 const int WorkspaceWindowResizer::kMinOnscreenHeight = 32;
 
 WorkspaceWindowResizer::~WorkspaceWindowResizer() {
-  ash::Shell::GetInstance()->cursor_manager()->UnlockCursor();
+  Shell* shell = Shell::GetInstance();
+  if (ShouldAllowCursorWarp())
+    shell->display_controller()->set_allow_warp_during_lock(false);
+  shell->cursor_manager()->UnlockCursor();
 }
 
 // static
@@ -61,9 +69,23 @@ WorkspaceWindowResizer* WorkspaceWindowResizer::Create(
 }
 
 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_root = actual_location.second;
+  gfx::Point location_in_screen = actual_location.second;
+  aura::client::GetScreenPositionClient(current_root)->
+      ConvertPointToScreen(current_root, &location_in_screen);
+
+  // TODO(yusukes): Implement dragging a window from one display to another.
+  if (current_root != window()->GetRootWindow())
+    return;
+
   int grid_size = event_flags & ui::EF_CONTROL_DOWN ?
                   0 : ash::Shell::GetInstance()->GetGridSize();
-  gfx::Rect bounds = CalculateBoundsForDrag(details_, location, grid_size);
+  gfx::Rect bounds =
+      CalculateBoundsForDrag(details_, location_in_root, grid_size);
 
   if (wm::IsWindowNormal(details_.window))
     AdjustBoundsForMainWindow(&bounds, grid_size);
@@ -72,7 +94,7 @@ void WorkspaceWindowResizer::Drag(const gfx::Point& location, int event_flags) {
       RestackWindows();
     did_move_or_resize_ = true;
   }
-  UpdatePhantomWindow(location, bounds, grid_size);
+  UpdatePhantomWindow(location_in_root, bounds, grid_size);
   if (!attached_windows_.empty())
     LayoutAttachedWindows(bounds, grid_size);
   if (bounds != details_.window->bounds())
@@ -164,7 +186,11 @@ WorkspaceWindowResizer::WorkspaceWindowResizer(
       snap_type_(SNAP_NONE),
       num_mouse_moves_since_bounds_change_(0) {
   DCHECK(details_.is_resizable);
-  ash::Shell::GetInstance()->cursor_manager()->LockCursor();
+
+  Shell* shell = Shell::GetInstance();
+  shell->cursor_manager()->LockCursor();
+  if (ShouldAllowCursorWarp())
+    shell->display_controller()->set_allow_warp_during_lock(true);

[sky, 2012/08/03 17:07:18]

I don't get why we need this. Can't it be inferred?

[Yusuke Sato, 2012/08/03 23:18:45]

I think we need to confine a mouse pointer in one display while dragging except
when the component being dragged is HTCAPTION. For example, I think it should be
confined in one display during resizing a window because the window cannot span
two displays at the same time anyway. 

Since ash::DisplayController does not know which component is being dragged, I
put the ShouldAllowCursorWarp() function here.

 
   // Only support attaching to the right/bottom.
   DCHECK(attached_windows_.empty() ||
@@ -441,5 +467,11 @@ WorkspaceWindowResizer::SnapType WorkspaceWindowResizer::GetSnapType(
   return SNAP_NONE;
 }
 
+bool WorkspaceWindowResizer::ShouldAllowCursorWarp() 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