ui: Add default implementations for EventHandler interface.

This allows getting rid of a whole bunch of noop implementations, and makes
it easier to add new event types to be dispatched through the EventDispatcher
to EventHandlers.

BUG=159632

Review URL: https://codereview.chromium.org/11348145

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168817 0039d316-1c4b-4281-b951-d872f2087c98

51 files changed, 45 insertions, 470 deletions

diff --git a/ash/accelerators/accelerator_filter.cc b/ash/accelerators/accelerator_filter.cc
index 69ba103..51c4450 100644
--- a/ash/accelerators/accelerator_filter.cc
+++ b/ash/accelerators/accelerator_filter.cc
@@ -90,21 +90,5 @@ ui::EventResult AcceleratorFilter::OnKeyEvent(ui::KeyEvent* event) {
       ui::ER_CONSUMED : ui::ER_UNHANDLED;
 }
 
-ui::EventResult AcceleratorFilter::OnMouseEvent(ui::MouseEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult AcceleratorFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult AcceleratorFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult AcceleratorFilter::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 }  // namespace internal
 }  // namespace ash
diff --git a/ash/accelerators/accelerator_filter.h b/ash/accelerators/accelerator_filter.h
index e9ac992..2f125c4 100644
--- a/ash/accelerators/accelerator_filter.h
+++ b/ash/accelerators/accelerator_filter.h
@@ -22,10 +22,6 @@ class ASH_EXPORT AcceleratorFilter : public ui::EventHandler {
 
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
-  virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AcceleratorFilter);
diff --git a/ash/display/mouse_cursor_event_filter.cc b/ash/display/mouse_cursor_event_filter.cc
index 0cb8723..74514a4 100644
--- a/ash/display/mouse_cursor_event_filter.cc
+++ b/ash/display/mouse_cursor_event_filter.cc
@@ -71,10 +71,6 @@ void MouseCursorEventFilter::HideSharedEdgeIndicator() {
   shared_display_edge_indicator_->Hide();
 }
 
-ui::EventResult MouseCursorEventFilter::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult MouseCursorEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   // Handle both MOVED and DRAGGED events here because when the mouse pointer
   // enters the other root window while dragging, the underlying window system
@@ -91,19 +87,6 @@ ui::EventResult MouseCursorEventFilter::OnMouseEvent(ui::MouseEvent* event) {
       ui::ER_CONSUMED : ui::ER_UNHANDLED;
 }
 
-ui::EventResult MouseCursorEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult MouseCursorEventFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult MouseCursorEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 bool MouseCursorEventFilter::WarpMouseCursorIfNecessary(
     aura::RootWindow* target_root,
     const gfx::Point& point_in_screen) {
diff --git a/ash/display/mouse_cursor_event_filter.h b/ash/display/mouse_cursor_event_filter.h
index 48a370d..a1be91c 100644
--- a/ash/display/mouse_cursor_event_filter.h
+++ b/ash/display/mouse_cursor_event_filter.h
@@ -47,11 +47,7 @@ class ASH_EXPORT MouseCursorEventFilter : public ui::EventHandler {
   void HideSharedEdgeIndicator();
 
   // Overridden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(MouseCursorEventFilterTest, SetMouseWarpModeFlag);
diff --git a/ash/drag_drop/drag_drop_controller.cc b/ash/drag_drop/drag_drop_controller.cc
index 7234b30..da30919 100644
--- a/ash/drag_drop/drag_drop_controller.cc
+++ b/ash/drag_drop/drag_drop_controller.cc
@@ -230,10 +230,6 @@ ui::EventResult DragDropController::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_CONSUMED;
 }
 
-ui::EventResult DragDropController::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult DragDropController::OnTouchEvent(ui::TouchEvent* event) {
   // TODO(sad): Also check for the touch-id.
   // TODO(varunjain): Add code for supporting drag-and-drop across displays
@@ -257,10 +253,6 @@ ui::EventResult DragDropController::OnTouchEvent(ui::TouchEvent* event) {
   return ui::ER_CONSUMED;
 }
 
-ui::EventResult DragDropController::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 void DragDropController::OnWindowDestroyed(aura::Window* window) {
   if (drag_window_ == window) {
     drag_window_->RemoveObserver(this);
diff --git a/ash/drag_drop/drag_drop_controller.h b/ash/drag_drop/drag_drop_controller.h
index a0e8629..ad897df 100644
--- a/ash/drag_drop/drag_drop_controller.h
+++ b/ash/drag_drop/drag_drop_controller.h
@@ -66,9 +66,7 @@ class ASH_EXPORT DragDropController
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::WindowObserver.
   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
diff --git a/ash/extended_desktop_unittest.cc b/ash/extended_desktop_unittest.cc
index 741287b..37b5572 100644
--- a/ash/extended_desktop_unittest.cc
+++ b/ash/extended_desktop_unittest.cc
@@ -89,10 +89,6 @@ class MoveWindowByClickEventFilter : public ui::EventHandler {
 
  private:
   // ui::EventHandler overrides:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE {
     if (event->type() == ui::ET_MOUSE_RELEASED) {
       Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
@@ -102,18 +98,6 @@ class MoveWindowByClickEventFilter : public ui::EventHandler {
     return ui::ER_UNHANDLED;
   }
 
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
   aura::Window* target_;
   DISALLOW_COPY_AND_ASSIGN(MoveWindowByClickEventFilter);
 };
diff --git a/ash/launcher/launcher_tooltip_manager.cc b/ash/launcher/launcher_tooltip_manager.cc
index a218aba..9768aa8 100644
--- a/ash/launcher/launcher_tooltip_manager.cc
+++ b/ash/launcher/launcher_tooltip_manager.cc
@@ -254,10 +254,6 @@ bool LauncherTooltipManager::IsVisible() {
   return widget_ && widget_->IsVisible();
 }
 
-ui::EventResult LauncherTooltipManager::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult LauncherTooltipManager::OnMouseEvent(ui::MouseEvent* event) {
   DCHECK(event->target());
   DCHECK(event);
@@ -293,10 +289,6 @@ ui::EventResult LauncherTooltipManager::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult LauncherTooltipManager::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult LauncherTooltipManager::OnTouchEvent(ui::TouchEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
   if (widget_ && widget_->IsVisible() && widget_->GetNativeWindow() != target)
diff --git a/ash/launcher/launcher_tooltip_manager.h b/ash/launcher/launcher_tooltip_manager.h
index 874fa63..5adea3c 100644
--- a/ash/launcher/launcher_tooltip_manager.h
+++ b/ash/launcher/launcher_tooltip_manager.h
@@ -71,9 +71,7 @@ class ASH_EXPORT LauncherTooltipManager : public ui::EventHandler,
 
 protected:
   // ui::EventHandler overrides:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
   virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
diff --git a/ash/magnifier/magnification_controller.cc b/ash/magnifier/magnification_controller.cc
index 63b0307..4427a11 100644
--- a/ash/magnifier/magnification_controller.cc
+++ b/ash/magnifier/magnification_controller.cc
@@ -117,11 +117,8 @@ class MagnificationControllerImpl : virtual public MagnificationController,
   void ValidateScale(float* scale);
 
   // ui::EventHandler overrides:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
   virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   aura::RootWindow* root_window_;
 
@@ -450,10 +447,6 @@ bool MagnificationControllerImpl::IsEnabled() const {
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationControllerImpl: aura::EventFilter implementation
 
-ui::EventResult MagnificationControllerImpl::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult MagnificationControllerImpl::OnMouseEvent(
     ui::MouseEvent* event) {
   if (IsMagnified() && event->type() == ui::ET_MOUSE_MOVED) {
@@ -492,16 +485,6 @@ ui::EventResult MagnificationControllerImpl::OnScrollEvent(
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult MagnificationControllerImpl::OnTouchEvent(
-    ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult MagnificationControllerImpl::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationController:
 
diff --git a/ash/magnifier/partial_magnification_controller.cc b/ash/magnifier/partial_magnification_controller.cc
index 7b682a7..cdabbf2 100644
--- a/ash/magnifier/partial_magnification_controller.cc
+++ b/ash/magnifier/partial_magnification_controller.cc
@@ -76,11 +76,6 @@ void PartialMagnificationController::SetEnabled(bool enabled) {
 ////////////////////////////////////////////////////////////////////////////////
 // PartialMagnificationController: ui::EventHandler implementation
 
-ui::EventResult PartialMagnificationController::OnKeyEvent(
-    ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult PartialMagnificationController::OnMouseEvent(
     ui::MouseEvent* event) {
   if (IsPartialMagnified() && event->type() == ui::ET_MOUSE_MOVED) {
@@ -100,21 +95,6 @@ ui::EventResult PartialMagnificationController::OnMouseEvent(
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult PartialMagnificationController::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult PartialMagnificationController::OnTouchEvent(
-    ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult PartialMagnificationController::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // PartialMagnificationController: aura::WindowObserver implementation
 
diff --git a/ash/magnifier/partial_magnification_controller.h b/ash/magnifier/partial_magnification_controller.h
index 7908d97..24e57d3 100644
--- a/ash/magnifier/partial_magnification_controller.h
+++ b/ash/magnifier/partial_magnification_controller.h
@@ -67,11 +67,7 @@ class PartialMagnificationController
   void RemoveZoomWidgetObservers();
 
   // ui::EventHandler overrides:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from WindowObserver:
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
diff --git a/ash/system/tray/tray_event_filter.cc b/ash/system/tray/tray_event_filter.cc
index 0c6afc0..01a751b 100644
--- a/ash/system/tray/tray_event_filter.cc
+++ b/ash/system/tray/tray_event_filter.cc
@@ -28,10 +28,6 @@ TrayEventFilter::~TrayEventFilter() {
   ash::Shell::GetInstance()->RemovePreTargetHandler(this);
 }
 
-ui::EventResult TrayEventFilter::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult TrayEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   if (event->type() == ui::ET_MOUSE_PRESSED &&
       ProcessLocatedEvent(event)) {
@@ -40,10 +36,6 @@ ui::EventResult TrayEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult TrayEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult TrayEventFilter::OnTouchEvent(ui::TouchEvent* event) {
   if (event->type() == ui::ET_TOUCH_PRESSED &&
       ProcessLocatedEvent(event)) {
@@ -52,10 +44,6 @@ ui::EventResult TrayEventFilter::OnTouchEvent(ui::TouchEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult TrayEventFilter::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 bool TrayEventFilter::ProcessLocatedEvent(ui::LocatedEvent* event) {
   if (event->target()) {
     aura::Window* target = static_cast<aura::Window*>(event->target());
diff --git a/ash/system/tray/tray_event_filter.h b/ash/system/tray/tray_event_filter.h
index 02194b7..dd86f3b 100644
--- a/ash/system/tray/tray_event_filter.h
+++ b/ash/system/tray/tray_event_filter.h
@@ -26,11 +26,8 @@ class TrayEventFilter : public ui::EventHandler {
   virtual ~TrayEventFilter();
 
   // Overridden from ui::EventHandler.
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   // Returns true if the event is handled.
diff --git a/ash/tooltips/tooltip_controller.cc b/ash/tooltips/tooltip_controller.cc
index aa19e31..c13bcdd 100644
--- a/ash/tooltips/tooltip_controller.cc
+++ b/ash/tooltips/tooltip_controller.cc
@@ -300,10 +300,6 @@ ui::EventResult TooltipController::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult TooltipController::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult TooltipController::OnTouchEvent(ui::TouchEvent* event) {
   // TODO(varunjain): need to properly implement tooltips for
   // touch events.
@@ -316,10 +312,6 @@ ui::EventResult TooltipController::OnTouchEvent(ui::TouchEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult TooltipController::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 void TooltipController::OnWindowDestroyed(aura::Window* window) {
   if (tooltip_window_ == window) {
     tooltip_window_->RemoveObserver(this);
diff --git a/ash/tooltips/tooltip_controller.h b/ash/tooltips/tooltip_controller.h
index dba89d2..67c6f77 100644
--- a/ash/tooltips/tooltip_controller.h
+++ b/ash/tooltips/tooltip_controller.h
@@ -44,9 +44,7 @@ class ASH_EXPORT TooltipController : public aura::client::TooltipClient,
   // Overridden from ui::EventHandler.
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::WindowObserver.
   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
diff --git a/ash/touch/touch_observer_hud.cc b/ash/touch/touch_observer_hud.cc
index b33d500..22dc029 100644
--- a/ash/touch/touch_observer_hud.cc
+++ b/ash/touch/touch_observer_hud.cc
@@ -182,18 +182,6 @@ void TouchObserverHUD::UpdateTouchPointLabel(int index) {
   touch_labels_[index]->SetText(UTF8ToUTF16(string));
 }
 
-ui::EventResult TouchObserverHUD::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult TouchObserverHUD::OnMouseEvent(ui::MouseEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult TouchObserverHUD::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult TouchObserverHUD::OnTouchEvent(ui::TouchEvent* event) {
   if (event->touch_id() >= kMaxTouchPoints)
     return ui::ER_UNHANDLED;
@@ -213,10 +201,6 @@ ui::EventResult TouchObserverHUD::OnTouchEvent(ui::TouchEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult TouchObserverHUD::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 void TouchObserverHUD::OnWidgetClosing(views::Widget* widget) {
   DCHECK_EQ(widget, widget_);
   widget_ = NULL;
diff --git a/ash/touch/touch_observer_hud.h b/ash/touch/touch_observer_hud.h
index ccfb23d..03c1bac 100644
--- a/ash/touch/touch_observer_hud.h
+++ b/ash/touch/touch_observer_hud.h
@@ -35,11 +35,7 @@ class TouchObserverHUD : public ui::EventHandler,
   void UpdateTouchPointLabel(int index);
 
   // Overriden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
-  virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from views::WidgetObserver:
   virtual void OnWidgetClosing(views::Widget* widget) OVERRIDE;
diff --git a/ash/wm/app_list_controller.cc b/ash/wm/app_list_controller.cc
index ff50653..965210d 100644
--- a/ash/wm/app_list_controller.cc
+++ b/ash/wm/app_list_controller.cc
@@ -246,24 +246,12 @@ void AppListController::UpdateBounds() {
 ////////////////////////////////////////////////////////////////////////////////
 // AppListController, aura::EventFilter implementation:
 
-ui::EventResult AppListController::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult AppListController::OnMouseEvent(ui::MouseEvent* event) {
   if (event->type() == ui::ET_MOUSE_PRESSED)
     ProcessLocatedEvent(event);
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult AppListController::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult AppListController::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult AppListController::OnGestureEvent(ui::GestureEvent* event) {
   if (event->type() == ui::ET_GESTURE_TAP)
     ProcessLocatedEvent(event);
diff --git a/ash/wm/app_list_controller.h b/ash/wm/app_list_controller.h
index 0cb6982..119d136 100644
--- a/ash/wm/app_list_controller.h
+++ b/ash/wm/app_list_controller.h
@@ -76,10 +76,7 @@ class AppListController : public ui::EventHandler,
   void UpdateBounds();
 
   // ui::EventHandler overrides:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
   virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // aura::FocusChangeObserver overrides:
diff --git a/ash/wm/event_rewriter_event_filter.cc b/ash/wm/event_rewriter_event_filter.cc
index 7031581..fc36c0c 100644
--- a/ash/wm/event_rewriter_event_filter.cc
+++ b/ash/wm/event_rewriter_event_filter.cc
@@ -56,19 +56,5 @@ ui::EventResult EventRewriterEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult EventRewriterEventFilter::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult EventRewriterEventFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult EventRewriterEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 }  // namespace internal
 }  // namespace ash
diff --git a/ash/wm/event_rewriter_event_filter.h b/ash/wm/event_rewriter_event_filter.h
index 9473e99..f839064 100644
--- a/ash/wm/event_rewriter_event_filter.h
+++ b/ash/wm/event_rewriter_event_filter.h
@@ -29,9 +29,6 @@ class ASH_EXPORT EventRewriterEventFilter : public ui::EventHandler {
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   scoped_ptr<EventRewriterDelegate> delegate_;
 
diff --git a/ash/wm/overlay_event_filter.cc b/ash/wm/overlay_event_filter.cc
index 3540a0b..a0d02ce 100644
--- a/ash/wm/overlay_event_filter.cc
+++ b/ash/wm/overlay_event_filter.cc
@@ -59,18 +59,6 @@ ui::EventResult OverlayEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult OverlayEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult OverlayEventFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult OverlayEventFilter::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 void OverlayEventFilter::OnLoginStateChanged(
     user::LoginStatus status) {
   Cancel();
diff --git a/ash/wm/overlay_event_filter.h b/ash/wm/overlay_event_filter.h
index 31c7223..1eb18ed 100644
--- a/ash/wm/overlay_event_filter.h
+++ b/ash/wm/overlay_event_filter.h
@@ -53,9 +53,6 @@ class OverlayEventFilter : public ui::EventHandler,
   // ui::EventHandler overrides:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // ShellObserver overrides:
   virtual void OnLoginStateChanged(user::LoginStatus status) OVERRIDE;
diff --git a/ash/wm/panel_window_event_filter.cc b/ash/wm/panel_window_event_filter.cc
index 9891c87..52696aa 100644
--- a/ash/wm/panel_window_event_filter.cc
+++ b/ash/wm/panel_window_event_filter.cc
@@ -35,10 +35,6 @@ PanelWindowEventFilter::~PanelWindowEventFilter() {
   panel_container_->RemovePreTargetHandler(this);
 }
 
-ui::EventResult PanelWindowEventFilter::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult PanelWindowEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
   switch (event->type()) {
@@ -96,19 +92,6 @@ ui::EventResult PanelWindowEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   }
 }
 
-ui::EventResult PanelWindowEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult PanelWindowEventFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult PanelWindowEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 void PanelWindowEventFilter::OnWindowDestroying(aura::Window* window) {
   CHECK_EQ(panel_container_, window);
   delete this;
diff --git a/ash/wm/panel_window_event_filter.h b/ash/wm/panel_window_event_filter.h
index 88ca570..29971ad 100644
--- a/ash/wm/panel_window_event_filter.h
+++ b/ash/wm/panel_window_event_filter.h
@@ -30,11 +30,7 @@ class PanelWindowEventFilter : public ui::EventHandler,
   virtual ~PanelWindowEventFilter();
 
   // Overriden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::WindowObserver:
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
diff --git a/ash/wm/shelf_layout_manager.cc b/ash/wm/shelf_layout_manager.cc
index 5915d51..faf784c 100644
--- a/ash/wm/shelf_layout_manager.cc
+++ b/ash/wm/shelf_layout_manager.cc
@@ -74,11 +74,7 @@ class ShelfLayoutManager::AutoHideEventFilter : public ui::EventHandler {
   bool in_mouse_drag() const { return in_mouse_drag_; }
 
   // Overridden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   ShelfLayoutManager* shelf_;
@@ -98,11 +94,6 @@ ShelfLayoutManager::AutoHideEventFilter::~AutoHideEventFilter() {
   Shell::GetInstance()->RemovePreTargetHandler(this);
 }
 
-ui::EventResult ShelfLayoutManager::AutoHideEventFilter::OnKeyEvent(
-    ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult ShelfLayoutManager::AutoHideEventFilter::OnMouseEvent(
     ui::MouseEvent* event) {
   // This also checks IsShelfWindow() to make sure we don't attempt to hide the
@@ -116,21 +107,6 @@ ui::EventResult ShelfLayoutManager::AutoHideEventFilter::OnMouseEvent(
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult ShelfLayoutManager::AutoHideEventFilter::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult ShelfLayoutManager::AutoHideEventFilter::OnTouchEvent(
-    ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult ShelfLayoutManager::AutoHideEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 // ShelfLayoutManager:UpdateShelfObserver --------------------------------------
 
 // UpdateShelfObserver is used to delay updating the background until the
diff --git a/ash/wm/system_gesture_event_filter.cc b/ash/wm/system_gesture_event_filter.cc
index a918ee7..5e40f93 100644
--- a/ash/wm/system_gesture_event_filter.cc
+++ b/ash/wm/system_gesture_event_filter.cc
@@ -53,10 +53,6 @@ SystemGestureEventFilter::SystemGestureEventFilter()
 SystemGestureEventFilter::~SystemGestureEventFilter() {
 }
 
-ui::EventResult SystemGestureEventFilter::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult SystemGestureEventFilter::OnMouseEvent(ui::MouseEvent* event) {
 #if defined(OS_CHROMEOS)
   if (event->type() == ui::ET_MOUSE_PRESSED && event->native_event() &&
@@ -69,11 +65,6 @@ ui::EventResult SystemGestureEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult SystemGestureEventFilter::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult SystemGestureEventFilter::OnTouchEvent(ui::TouchEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
   touch_uma_.RecordTouchEvent(target, *event);
diff --git a/ash/wm/system_gesture_event_filter.h b/ash/wm/system_gesture_event_filter.h
index 23935f7..8d7843f 100644
--- a/ash/wm/system_gesture_event_filter.h
+++ b/ash/wm/system_gesture_event_filter.h
@@ -45,9 +45,7 @@ class SystemGestureEventFilter : public ui::EventHandler,
   virtual ~SystemGestureEventFilter();
 
   // Overridden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
   virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
diff --git a/ash/wm/system_modal_container_event_filter.cc b/ash/wm/system_modal_container_event_filter.cc
index 693e696..5103d2d 100644
--- a/ash/wm/system_modal_container_event_filter.cc
+++ b/ash/wm/system_modal_container_event_filter.cc
@@ -33,22 +33,5 @@ ui::EventResult SystemModalContainerEventFilter::OnMouseEvent(
                                                      ui::ER_CONSUMED;
 }
 
-ui::EventResult SystemModalContainerEventFilter::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult SystemModalContainerEventFilter::OnTouchEvent(
-    ui::TouchEvent* event) {
-  // TODO(sadrul): !
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult SystemModalContainerEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  // TODO(sad):
-  return ui::ER_UNHANDLED;
-}
-
 }  // namespace internal
 }  // namespace ash
diff --git a/ash/wm/system_modal_container_event_filter.h b/ash/wm/system_modal_container_event_filter.h
index b4cc2b6..64653ee 100644
--- a/ash/wm/system_modal_container_event_filter.h
+++ b/ash/wm/system_modal_container_event_filter.h
@@ -24,9 +24,6 @@ class ASH_EXPORT SystemModalContainerEventFilter : public ui::EventHandler {
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   SystemModalContainerEventFilterDelegate* delegate_;
diff --git a/ash/wm/toplevel_window_event_handler.cc b/ash/wm/toplevel_window_event_handler.cc
index c8d5769..987d4db 100644
--- a/ash/wm/toplevel_window_event_handler.cc
+++ b/ash/wm/toplevel_window_event_handler.cc
@@ -156,16 +156,6 @@ ui::EventResult ToplevelWindowEventHandler::OnMouseEvent(
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult ToplevelWindowEventHandler::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult ToplevelWindowEventHandler::OnTouchEvent(
-    ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult ToplevelWindowEventHandler::OnGestureEvent(
     ui::GestureEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
diff --git a/ash/wm/toplevel_window_event_handler.h b/ash/wm/toplevel_window_event_handler.h
index 142eca4..2304e25 100644
--- a/ash/wm/toplevel_window_event_handler.h
+++ b/ash/wm/toplevel_window_event_handler.h
@@ -40,8 +40,6 @@ class ASH_EXPORT ToplevelWindowEventHandler
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
   virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden form aura::client::WindowMoveClient:
diff --git a/ash/wm/window_cycle_controller.cc b/ash/wm/window_cycle_controller.cc
index c5e3641..046f812 100644
--- a/ash/wm/window_cycle_controller.cc
+++ b/ash/wm/window_cycle_controller.cc
@@ -35,10 +35,6 @@ class WindowCycleEventFilter : public ui::EventHandler {
 
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
-  virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
  private:
   DISALLOW_COPY_AND_ASSIGN(WindowCycleEventFilter);
 };
@@ -60,23 +56,6 @@ ui::EventResult WindowCycleEventFilter::OnKeyEvent(ui::KeyEvent* event) {
   return ui::ER_UNHANDLED;  // Always let the event propagate.
 }
 
-ui::EventResult WindowCycleEventFilter::OnMouseEvent(ui::MouseEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult WindowCycleEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult WindowCycleEventFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult WindowCycleEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 // Adds all the children of |window| to |windows|.
 void AddAllChildren(aura::Window* window,
                     WindowCycleList::WindowList* windows) {
diff --git a/ash/wm/window_modality_controller.cc b/ash/wm/window_modality_controller.cc
index d60bf96..1d60aa9 100644
--- a/ash/wm/window_modality_controller.cc
+++ b/ash/wm/window_modality_controller.cc
@@ -86,23 +86,12 @@ ui::EventResult WindowModalityController::OnMouseEvent(ui::MouseEvent* event) {
                                               ui::ER_UNHANDLED;
 }
 
-ui::EventResult WindowModalityController::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult WindowModalityController::OnTouchEvent(ui::TouchEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
   return ProcessLocatedEvent(target, event) ? ui::ER_CONSUMED :
                                               ui::ER_UNHANDLED;
 }
 
-ui::EventResult WindowModalityController::OnGestureEvent(
-    ui::GestureEvent* event) {
-  // TODO: make gestures work with modals.
-  return ui::ER_UNHANDLED;
-}
-
 void WindowModalityController::OnWindowInitialized(aura::Window* window) {
   windows_.push_back(window);
   window->AddObserver(this);
diff --git a/ash/wm/window_modality_controller.h b/ash/wm/window_modality_controller.h
index 6f685f6..c58136f8 100644
--- a/ash/wm/window_modality_controller.h
+++ b/ash/wm/window_modality_controller.h
@@ -40,9 +40,7 @@ class WindowModalityController : public ui::EventHandler,
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::EnvObserver:
   virtual void OnWindowInitialized(aura::Window* window) OVERRIDE;
diff --git a/ash/wm/workspace/frame_maximize_button.cc b/ash/wm/workspace/frame_maximize_button.cc
index 455bd80..2d2a57a 100644
--- a/ash/wm/workspace/frame_maximize_button.cc
+++ b/ash/wm/workspace/frame_maximize_button.cc
@@ -48,10 +48,6 @@ class FrameMaximizeButton::EscapeEventFilter : public ui::EventHandler {
 
   // EventFilter overrides:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
-  virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   FrameMaximizeButton* button_;
@@ -78,26 +74,6 @@ ui::EventResult FrameMaximizeButton::EscapeEventFilter::OnKeyEvent(
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult FrameMaximizeButton::EscapeEventFilter::OnMouseEvent(
-    ui::MouseEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult FrameMaximizeButton::EscapeEventFilter::OnScrollEvent(
-    ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult FrameMaximizeButton::EscapeEventFilter::OnTouchEvent(
-    ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult FrameMaximizeButton::EscapeEventFilter::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 // FrameMaximizeButton ---------------------------------------------------------
 
 FrameMaximizeButton::FrameMaximizeButton(views::ButtonListener* listener,
diff --git a/chrome/browser/ui/views/ash/tab_scrubber.cc b/chrome/browser/ui/views/ash/tab_scrubber.cc
index 5ae8e76..23e26b8 100644
--- a/chrome/browser/ui/views/ash/tab_scrubber.cc
+++ b/chrome/browser/ui/views/ash/tab_scrubber.cc
@@ -36,10 +36,6 @@ TabScrubber::TabScrubber()
 TabScrubber::~TabScrubber() {
 }
 
-ui::EventResult TabScrubber::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult TabScrubber::OnMouseEvent(ui::MouseEvent* event) {
   Browser* browser = GetActiveBrowser();
 
@@ -90,18 +86,6 @@ ui::EventResult TabScrubber::OnMouseEvent(ui::MouseEvent* event) {
   return ui::ER_CONSUMED;
 }
 
-ui::EventResult TabScrubber::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult TabScrubber::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult TabScrubber::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 void TabScrubber::Observe(int type,
                           const content::NotificationSource& source,
                           const content::NotificationDetails& details) {
diff --git a/chrome/browser/ui/views/ash/tab_scrubber.h b/chrome/browser/ui/views/ash/tab_scrubber.h
index 5f92ac0..a9da901 100644
--- a/chrome/browser/ui/views/ash/tab_scrubber.h
+++ b/chrome/browser/ui/views/ash/tab_scrubber.h
@@ -7,7 +7,6 @@
 
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
-#include "ui/aura/window.h"
 #include "ui/base/events/event_handler.h"
 
 class Browser;
@@ -27,11 +26,7 @@ class TabScrubber : public ui::EventHandler,
   virtual ~TabScrubber();
 
   // ui::EventHandler overrides:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // content::NotificationObserver overrides:
   virtual void Observe(int type,
diff --git a/ui/aura/aura.gyp b/ui/aura/aura.gyp
index 5797010..cac39fd 100644
--- a/ui/aura/aura.gyp
+++ b/ui/aura/aura.gyp
@@ -94,7 +94,6 @@
         'ui_controls_x11.cc',
         'window.cc',
         'window.h',
-        'window_delegate.cc',
         'window_delegate.h',
         'window_observer.h',
         'window_tracker.cc',
diff --git a/ui/aura/root_window_unittest.cc b/ui/aura/root_window_unittest.cc
index c97be64..ec35d99 100644
--- a/ui/aura/root_window_unittest.cc
+++ b/ui/aura/root_window_unittest.cc
@@ -649,18 +649,6 @@ class DeletingEventFilter : public ui::EventHandler {
     return ui::ER_UNHANDLED;
   }
 
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
   bool delete_during_pre_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(DeletingEventFilter);
diff --git a/ui/aura/window_delegate.cc b/ui/aura/window_delegate.cc
deleted file mode 100644
index 3302303..0000000
--- a/ui/aura/window_delegate.cc
+++ /dev/null
@@ -1,13 +0,0 @@
-// 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 "ui/aura/window_delegate.h"
-
-namespace aura {
-
-ui::EventResult WindowDelegate::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-}  // namespace aura
diff --git a/ui/aura/window_delegate.h b/ui/aura/window_delegate.h
index fb98de7..f79b469 100644
--- a/ui/aura/window_delegate.h
+++ b/ui/aura/window_delegate.h
@@ -102,9 +102,6 @@ class AURA_EXPORT WindowDelegate : public ui::EventHandler {
 
  protected:
   virtual ~WindowDelegate() {}
-
-  // Overridden from ui::EventHandler:
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
 };
 
 }  // namespace aura
diff --git a/ui/base/events/event_handler.cc b/ui/base/events/event_handler.cc
new file mode 100644
index 0000000..9ae82bf
--- /dev/null
+++ b/ui/base/events/event_handler.cc
@@ -0,0 +1,35 @@
+// 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 "ui/base/events/event_handler.h"
+
+namespace ui {
+
+EventHandler::EventHandler() {
+}
+
+EventHandler::~EventHandler() {
+}
+
+EventResult EventHandler::OnKeyEvent(KeyEvent* event) {
+  return ui::ER_UNHANDLED;
+}
+
+EventResult EventHandler::OnMouseEvent(MouseEvent* event) {
+  return ui::ER_UNHANDLED;
+}
+
+EventResult EventHandler::OnScrollEvent(ScrollEvent* event) {
+  return ui::ER_UNHANDLED;
+}
+
+EventResult EventHandler::OnTouchEvent(TouchEvent* event) {
+  return ui::ER_UNHANDLED;
+}
+
+EventResult EventHandler::OnGestureEvent(GestureEvent* event) {
+  return ui::ER_UNHANDLED;
+}
+
+}  // namespace ui
diff --git a/ui/base/events/event_handler.h b/ui/base/events/event_handler.h
index 84e6b6e..2221add 100644
--- a/ui/base/events/event_handler.h
+++ b/ui/base/events/event_handler.h
@@ -20,21 +20,22 @@ class TouchEvent;
 
 class EventTarget;
 
-// Dispatches events to appropriate targets.
+// Dispatches events to appropriate targets. The default implementations return
+// ER_UNHANDLED for all events.
 class UI_EXPORT EventHandler {
  public:
-  EventHandler() {}
-  virtual ~EventHandler() {}
+  EventHandler();
+  virtual ~EventHandler();
 
-  virtual EventResult OnKeyEvent(KeyEvent* event) = 0;
+  virtual EventResult OnKeyEvent(KeyEvent* event);
 
-  virtual EventResult OnMouseEvent(MouseEvent* event) = 0;
+  virtual EventResult OnMouseEvent(MouseEvent* event);
 
-  virtual EventResult OnScrollEvent(ScrollEvent* event) = 0;
+  virtual EventResult OnScrollEvent(ScrollEvent* event);
 
-  virtual EventResult OnTouchEvent(TouchEvent* event) = 0;
+  virtual EventResult OnTouchEvent(TouchEvent* event);
 
-  virtual EventResult OnGestureEvent(GestureEvent* event) = 0;
+  virtual EventResult OnGestureEvent(GestureEvent* event);
 };
 
 typedef std::vector<EventHandler*> EventHandlerList;
diff --git a/ui/ui.gyp b/ui/ui.gyp
index 07d80ac..8dd11c0 100644
--- a/ui/ui.gyp
+++ b/ui/ui.gyp
@@ -162,6 +162,7 @@
         'base/events/event_constants.h',
         'base/events/event_dispatcher.cc',
         'base/events/event_dispatcher.h',
+        'base/events/event_handler.cc',
         'base/events/event_handler.h',
         'base/events/event_target.cc',
         'base/events/event_target.h',
diff --git a/ui/views/corewm/compound_event_filter_unittest.cc b/ui/views/corewm/compound_event_filter_unittest.cc
index 6a0099d..d073200 100644
--- a/ui/views/corewm/compound_event_filter_unittest.cc
+++ b/ui/views/corewm/compound_event_filter_unittest.cc
@@ -64,22 +64,6 @@ class ConsumeGestureEventFilter : public ui::EventHandler {
 
  private:
   // Overridden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE {
-    return ui::ER_UNHANDLED;
-  }
-
   virtual ui::EventResult OnGestureEvent(ui::GestureEvent* e) OVERRIDE {
     return ui::ER_CONSUMED;
   }
diff --git a/ui/views/corewm/input_method_event_filter.cc b/ui/views/corewm/input_method_event_filter.cc
index a6ef49b..350ab4f 100644
--- a/ui/views/corewm/input_method_event_filter.cc
+++ b/ui/views/corewm/input_method_event_filter.cc
@@ -59,22 +59,6 @@ ui::EventResult InputMethodEventFilter::OnKeyEvent(ui::KeyEvent* event) {
   }
 }
 
-ui::EventResult InputMethodEventFilter::OnMouseEvent(ui::MouseEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult InputMethodEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult InputMethodEventFilter::OnTouchEvent(ui::TouchEvent* e) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult InputMethodEventFilter::OnGestureEvent(ui::GestureEvent* e) {
-  return ui::ER_UNHANDLED;
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // InputMethodEventFilter, ui::InputMethodDelegate implementation:
 
diff --git a/ui/views/corewm/input_method_event_filter.h b/ui/views/corewm/input_method_event_filter.h
index efcfbd2..99a42c3 100644
--- a/ui/views/corewm/input_method_event_filter.h
+++ b/ui/views/corewm/input_method_event_filter.h
@@ -39,10 +39,6 @@ class VIEWS_EXPORT InputMethodEventFilter
  private:
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
-  virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from ui::internal::InputMethodDelegate.
   virtual void DispatchKeyEventPostIME(const base::NativeEvent& event) OVERRIDE;
diff --git a/ui/views/widget/desktop_aura/x11_window_event_filter.cc b/ui/views/widget/desktop_aura/x11_window_event_filter.cc
index eb849e1..42269bd 100644
--- a/ui/views/widget/desktop_aura/x11_window_event_filter.cc
+++ b/ui/views/widget/desktop_aura/x11_window_event_filter.cc
@@ -88,10 +88,6 @@ void X11WindowEventFilter::SetUseHostWindowBorders(bool use_os_border) {
                   sizeof(MotifWmHints)/sizeof(long));
 }
 
-ui::EventResult X11WindowEventFilter::OnKeyEvent(ui::KeyEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 ui::EventResult X11WindowEventFilter::OnMouseEvent(ui::MouseEvent* event) {
   if (event->type() != ui::ET_MOUSE_PRESSED)
     return ui::ER_UNHANDLED;
@@ -111,18 +107,6 @@ ui::EventResult X11WindowEventFilter::OnMouseEvent(ui::MouseEvent* event) {
       ui::ER_CONSUMED : ui::ER_UNHANDLED;
 }
 
-ui::EventResult X11WindowEventFilter::OnScrollEvent(ui::ScrollEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult X11WindowEventFilter::OnTouchEvent(ui::TouchEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
-ui::EventResult X11WindowEventFilter::OnGestureEvent(ui::GestureEvent* event) {
-  return ui::ER_UNHANDLED;
-}
-
 bool X11WindowEventFilter::DispatchHostWindowDragMovement(
     int hittest,
     const gfx::Point& screen_location) {
diff --git a/ui/views/widget/desktop_aura/x11_window_event_filter.h b/ui/views/widget/desktop_aura/x11_window_event_filter.h
index 97d6be2..5f7bedc 100644
--- a/ui/views/widget/desktop_aura/x11_window_event_filter.h
+++ b/ui/views/widget/desktop_aura/x11_window_event_filter.h
@@ -39,11 +39,7 @@ class VIEWS_EXPORT X11WindowEventFilter : public ui::EventHandler {
   void SetUseHostWindowBorders(bool use_os_border);
 
   // Overridden from ui::EventHandler:
-  virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
-  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   // Dispatches a _NET_WM_MOVERESIZE message to the window manager to tell it