Refactors away method implementations in ui::EventTargeter

ui/aura/window_targeter.h

 // Copyright (c) 2013 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 UI_AURA_WINDOW_TARGETER_H_
 #define UI_AURA_WINDOW_TARGETER_H_
 
 #include "ui/aura/aura_export.h"
 #include "ui/events/event_targeter.h"
 
 namespace aura {
 
 class Window;
 
 class AURA_EXPORT WindowTargeter : public ui::EventTargeter {
  public:
   WindowTargeter();
   ~WindowTargeter() override;
 
+  // Returns true if |target| or one of its descendants can be a target of
+  // |event|. This requires that |target| and its descendants are not
+  // prohibited from accepting the event, and that the event is within an
+  // actionable region of the target's bounds. Note that the location etc. of
+  // |event| is in |target|'s parent's coordinate system.
+  virtual bool SubtreeShouldBeExploredForEvent(ui::EventTarget* target,
+                                               const ui::LocatedEvent& event);
+
  protected:
+  // Same as FindTargetForEvent(), but used for positional events. The location
+  // etc. of |event| are in |root|'s coordinate system. When finding the target
+  // for the event, the targeter can mutate the |event| (e.g. change the
+  // coordinate to be in the returned target's coordinate system) so that it can
+  // be dispatched to the target without any further modification.
+  virtual ui::EventTarget* FindTargetForLocatedEvent(ui::EventTarget* root,

[tdanderson, 2015/05/13 18:38:25]

Since these four methods are being removed from the EventTargeter interface and
will only live in WindowTargeter, I wonder if it would be better to use the
Window* type instead of the ui::EventTarget* type in the method parameter lists
/ return values.

[varkha, 2015/05/21 19:11:04]

Done. Seems like there are fewer casts than before so this is definitely
positive.

+                                                     ui::LocatedEvent* event);
+
+  // Returns false if neither |target| nor any of its descendants are allowed
+  // to accept |event| for reasons unrelated to the event's location or the
+  // target's bounds. For example, overrides of this function may consider
+  // attributes such as the visibility or enabledness of |target|. Note that
+  // the location etc. of |event| is in |target|'s parent's coordinate system.
+  virtual bool SubtreeCanAcceptEvent(ui::EventTarget* target,
+                                     const ui::LocatedEvent& event) const;
+
+  // Returns whether the location of the event is in an actionable region of the
+  // target. Note that the location etc. of |event| is in the |target|'s
+  // parent's coordinate system.
+  virtual bool EventLocationInsideBounds(ui::EventTarget* target,
+                                         const ui::LocatedEvent& event) const;
+
   // ui::EventTargeter:
   ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
                                       ui::Event* event) override;
-  ui::EventTarget* FindTargetForLocatedEvent(ui::EventTarget* root,
-                                             ui::LocatedEvent* event) override;
-  bool SubtreeCanAcceptEvent(ui::EventTarget* target,
-                             const ui::LocatedEvent& event) const override;
-  bool EventLocationInsideBounds(ui::EventTarget* target,
-                                 const ui::LocatedEvent& event) const override;
-
  private:
-  Window* FindTargetForKeyEvent(Window* root_window,
-                                const ui::KeyEvent& event);
+  Window* FindTargetForKeyEvent(Window* root_window, const ui::KeyEvent& event);
+  Window* FindTargetForNonKeyEvent(Window* root_window, ui::Event* event);
   Window* FindTargetInRootWindow(Window* root_window,
                                  const ui::LocatedEvent& event);
+  ui::EventTarget* FindTargetForEventRecursively(Window* root_window,

[tdanderson, 2015/05/13 18:38:25]

nit: FindTargetForLocatedEventRecursively?

[varkha, 2015/05/21 19:11:04]

Done.

+                                                 ui::LocatedEvent* event);
 
   DISALLOW_COPY_AND_ASSIGN(WindowTargeter);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_TARGETER_H_