Allow the cursor to warp even when a window is dragged

ash/wm/coordinate_conversion.cc

Index: ash/wm/coordinate_conversion.cc
diff --git a/ash/wm/coordinate_conversion.cc b/ash/wm/coordinate_conversion.cc
new file mode 100644
index 0000000000000000000000000000000000000000..55dd25a15ee7a36060d0f863ba7daacd92303dc8
--- /dev/null
+++ b/ash/wm/coordinate_conversion.cc
@@ -0,0 +1,91 @@
+// 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/coordinate_conversion.h"
+
+#include "ash/display/display_controller.h"
+#include "ash/shell.h"
+#include "ui/aura/client/screen_position_client.h"
+#include "ui/aura/root_window.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/point.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/screen.h"
+
+namespace ash {
+namespace wm {
+
+aura::RootWindow* GetRootWindowAt(const gfx::Point& point) {
+  const gfx::Display& display = gfx::Screen::GetDisplayNearestPoint(point);
+  // TODO(yusukes): Move coordinate_conversion.cc and .h to ui/aura/ once
+  // GetRootWindowForDisplayId() is moved to aura::Env.
+  return Shell::GetInstance()->display_controller()->
+      GetRootWindowForDisplayId(display.id());
+}
+
+aura::RootWindow* GetRootWindowMatching(const gfx::Rect& rect) {
+  const gfx::Display& display = gfx::Screen::GetDisplayMatching(rect);
+  return Shell::GetInstance()->display_controller()->
+      GetRootWindowForDisplayId(display.id());
+}
+
+std::pair<aura::RootWindow*, gfx::Point> GetRootWindowRelativeToWindow(
+    aura::Window* window,
+    const gfx::Point& location) {
+  aura::RootWindow* root_window = window->GetRootWindow();
+  gfx::Point location_in_root(location);
+  aura::Window::ConvertPointToWindow(window, root_window, &location_in_root);
+
+#if defined(USE_X11)
+  // This conversion is necessary for dealing with the "pointer warp" feature in
+  // ash/display/display_controller.cc. For example, if we have two displays,
+  // say 1000x1000 (primary) and 500x500 (extended one on the right), and start
+  // dragging a window at (999, 123), and then move the pointer to the right,
+  // the pointer suddenly warps to the extended display. The destination is
+  // (0, 123) in the secondary root window's coordinates, or (1000, 123) in the
+  // screen coordinates. However, since the mouse is captured during drag, a
+  // weird LocatedEvent, something like (0, 1123) in the *primary* root window's
+  // coordinates, is sent to Chrome (Remember that in the native X11 world, the
+  // two root windows are always stacked vertically regardless of the display
+  // layout in Ash). We need to figure out that (0, 1123) in the primary root
+  // window's coordinates is actually (0, 123) in the extended root window's
+  // coordinates.
+  if (!root_window->ContainsPointInRoot(location_in_root)) {
+    gfx::Point location_in_native = location_in_root;
+    root_window->ConvertPointToNativeScreen(&location_in_native);
+
+    Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
+    for (size_t i = 0; i < root_windows.size(); ++i) {
+      gfx::Point native_origin = root_windows[i]->bounds().origin();
+      root_windows[i]->ConvertPointToNativeScreen(&native_origin);
+      gfx::Rect native_bounds = root_windows[i]->bounds();
+      native_bounds.set_origin(native_origin);
+      if (native_bounds.Contains(location_in_native)) {
+        root_window = root_windows[i];
+        location_in_root = location_in_native;
+        location_in_root.Offset(-native_bounds.x(), -native_bounds.y());
+        break;
+      }
+    }
+  }
+#else
+  // TODO(yusukes): Support non-X11 platforms if necessary.
+#endif
+
+  return std::make_pair(root_window, location_in_root);
+}
+
+void ConvertPointToScreen(aura::Window* window, gfx::Point* point) {
+  aura::client::GetScreenPositionClient(window->GetRootWindow())->
+      ConvertPointToScreen(window, point);
+}
+
+void ConvertPointFromScreen(aura::Window* window,
+                            gfx::Point* point_in_screen) {
+  aura::client::GetScreenPositionClient(window->GetRootWindow())->
+      ConvertPointFromScreen(window, point_in_screen);
+}
+
+}  // namespace wm
+}  // namespace ash