Splits ToplevelWindowEventHandler into two

ash/wm/common/wm_toplevel_window_event_handler.h

+// 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_WM_WM_TOPLEVEL_WINDOW_EVENT_HANDLER_H_
+#define ASH_WM_WM_TOPLEVEL_WINDOW_EVENT_HANDLER_H_
+
+#include <memory>
+
+#include "ash/wm/common/ash_wm_common_export.h"
+#include "ash/wm/common/wm_display_observer.h"
+#include "ash/wm/common/wm_types.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/wm/public/window_move_client.h"
+
+namespace ui {
+class KeyEvent;
+class LocatedEvent;
+class MouseEvent;
+class GestureEvent;
+}
+
+namespace ash {
+
+class WindowResizer;
+
+namespace wm {
+
+class WmGlobals;
+class WmWindow;
+
+// WmToplevelWindowEventHandler handles dragging and resizing of top level
+// windows. WmToplevelWindowEventHandler is forwarded events, such as from an
+// EventHandler.

[James Cook, 2016/05/21 18:28:21]

Nice class comment.

+class ASH_WM_COMMON_EXPORT WmToplevelWindowEventHandler
+    : public WmDisplayObserver {
+ public:
+  // Describes what triggered ending the drag.
+  enum class EndReason {

[James Cook, 2016/05/21 18:28:21]

I would call this DragEndReason or DragResult or something that helps tie it to
drags. My first reaction on seeing WmToplevelWindowEventHandler::EndReason in
other code is "what ended"?

[sky, 2016/05/23 15:48:52]

I went with DragResult.

+    // The drag successfully completed.
+    SUCCESS,
+
+    REVERT,
+
+    // The underlying window was destroyed while the drag is in process.
+    WINDOW_DESTROYED
+  };
+  using EndClosure = base::Callback<void(EndReason)>;
+
+  explicit WmToplevelWindowEventHandler(WmGlobals* globals);
+  ~WmToplevelWindowEventHandler() override;
+
+  void OnKeyEvent(ui::KeyEvent* event);
+  void OnMouseEvent(ui::MouseEvent* event, WmWindow* target);
+  void OnGestureEvent(ui::GestureEvent* event, WmWindow* target);
+
+  // Attempts to start a drag if one is not already in progress. Returns true if
+  // successful. |end_closure| is run when the drag completes. |end_closure| is
+  // not run if the drag does not start.
+  bool AttemptToStartDrag(WmWindow* window,
+                          const gfx::Point& point_in_parent,
+                          int window_component,
+                          aura::client::WindowMoveSource source,
+                          const EndClosure& end_closure);
+
+  // If there is a drag in progress it is reverted, otherwise does nothing.
+  void RevertDrag();
+
+  // Returns true if there is a drag in progress.
+  bool is_drag_in_progress() const { return window_resizer_.get() != nullptr; }

[James Cook, 2016/05/21 18:28:21]

I don't think this is used. (Man, I wish we had search-in-cl UI, like critique.)

[sky, 2016/05/23 15:48:52]

I use it in a subsequent patch. But I'll add it there.

+
+ private:
+  class ScopedWindowResizer;
+
+  // Completes or reverts the drag if one is in progress. Returns true if a
+  // drag was completed or reverted.
+  bool CompleteDrag(EndReason reason);
+
+  void HandleMousePressed(WmWindow* target, ui::MouseEvent* event);
+  void HandleMouseReleased(WmWindow* target, ui::MouseEvent* event);
+
+  // Called during a drag to resize/position the window.
+  void HandleDrag(WmWindow* target, ui::LocatedEvent* event);
+
+  // Called during mouse moves to update window resize shadows.
+  void HandleMouseMoved(WmWindow* target, ui::LocatedEvent* event);
+
+  // Called for mouse exits to hide window resize shadows.
+  void HandleMouseExited(WmWindow* target, ui::LocatedEvent* event);
+
+  // Called when mouse capture is lost.
+  void HandleCaptureLost(ui::LocatedEvent* event);
+
+  // Sets |window|'s state type to |new_state_type|. Called after the drag has
+  // been completed for fling gestures.
+  void SetWindowStateTypeFromGesture(WmWindow* window,
+                                     wm::WindowStateType new_state_type);
+
+  // Invoked from ScopedWindowResizer if the window is destroyed.
+  void ResizerWindowDestroyed();
+
+  // WmDisplayObserver:
+  void OnDisplayConfigurationChanging() override;
+
+  WmGlobals* globals_;
+
+  // The hittest result for the first finger at the time that it initially
+  // touched the screen. |first_finger_hittest_| is one of ui/base/hit_test.h
+  int first_finger_hittest_;
+
+  // The window bounds when the drag was started. When a window is minimized,
+  // maximized or snapped via a swipe/fling gesture, the restore bounds should
+  // be set to the bounds of the window when the drag was started.
+  gfx::Rect pre_drag_window_bounds_;
+
+  // Is a window move/resize in progress because of gesture events?
+  bool in_gesture_drag_ = false;

[James Cook, 2016/05/21 18:28:21]

optional nit: Consider initializing this in the .cc file, because doing it here
makes first_finger_hittest_ look maybe-uninitialized, but it's initialized in
the cc I presume to avoid the hit_test.h #include.

[sky, 2016/05/23 15:48:52]

I agree with you, but I think it's just something we have to get use to with
c++11.
Exactly.

+
+  std::unique_ptr<ScopedWindowResizer> window_resizer_;
+
+  EndClosure end_closure_;
+
+  DISALLOW_COPY_AND_ASSIGN(WmToplevelWindowEventHandler);
+};
+
+}  // namespace wm
+}  // namespace ash
+
+#endif  // ASH_WM_WM_TOPLEVEL_WINDOW_EVENT_HANDLER_H_