events: Change gesture-event handler in EventHandler to not return any values.

The EventHandler overriddes should mark the event as having been processed
(Event::SetHandled) when the event triggered an action, or stop the propagation
of the event (Event::StopPropagation) as appropriate (when the handler destroyed
the event-target, for example).

BUG=163618

Review URL: https://codereview.chromium.org/11280290

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@170890 0039d316-1c4b-4281-b951-d872f2087c98

13 files changed, 45 insertions, 43 deletions

diff --git a/ui/views/widget/desktop_aura/desktop_activation_client.cc b/ui/views/widget/desktop_aura/desktop_activation_client.cc
index b53feba..a099e48 100644
--- a/ui/views/widget/desktop_aura/desktop_activation_client.cc
+++ b/ui/views/widget/desktop_aura/desktop_activation_client.cc
@@ -164,13 +164,11 @@ ui::EventResult DesktopActivationClient::OnTouchEvent(ui::TouchEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult DesktopActivationClient::OnGestureEvent(
-    ui::GestureEvent* event) {
+void DesktopActivationClient::OnGestureEvent(ui::GestureEvent* event) {
   if (event->type() == ui::ET_GESTURE_BEGIN &&
       event->details().touch_points() == 1) {
     FocusWindowWithEvent(event);
   }
-  return ui::ER_UNHANDLED;
 }
 
 void DesktopActivationClient::FocusWindowWithEvent(const ui::Event* event) {
diff --git a/ui/views/widget/desktop_aura/desktop_activation_client.h b/ui/views/widget/desktop_aura/desktop_activation_client.h
index 87b1299..55ade7f 100644
--- a/ui/views/widget/desktop_aura/desktop_activation_client.h
+++ b/ui/views/widget/desktop_aura/desktop_activation_client.h
@@ -62,7 +62,7 @@ class VIEWS_EXPORT DesktopActivationClient
   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;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
   void FocusWindowWithEvent(const ui::Event* event);
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index 87b8bf1..870b878 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -572,9 +572,8 @@ ui::EventResult DesktopNativeWidgetAura::OnTouchEvent(ui::TouchEvent* event) {
   return native_widget_delegate_->OnTouchEvent(event);
 }
 
-ui::EventResult DesktopNativeWidgetAura::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return native_widget_delegate_->OnGestureEvent(event);
+void DesktopNativeWidgetAura::OnGestureEvent(ui::GestureEvent* event) {
+  native_widget_delegate_->OnGestureEvent(event);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.h b/ui/views/widget/desktop_aura/desktop_native_widget_aura.h
index 742b133..b3abe0f 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.h
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.h
@@ -153,7 +153,7 @@ class VIEWS_EXPORT DesktopNativeWidgetAura
   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;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::client::ActivationDelegate:
   virtual bool ShouldActivate() const OVERRIDE;
diff --git a/ui/views/widget/native_widget_aura.cc b/ui/views/widget/native_widget_aura.cc
index f0779c3..0d804a6 100644
--- a/ui/views/widget/native_widget_aura.cc
+++ b/ui/views/widget/native_widget_aura.cc
@@ -841,9 +841,9 @@ ui::EventResult NativeWidgetAura::OnTouchEvent(ui::TouchEvent* event) {
   return delegate_->OnTouchEvent(event);
 }
 
-ui::EventResult NativeWidgetAura::OnGestureEvent(ui::GestureEvent* event) {
+void NativeWidgetAura::OnGestureEvent(ui::GestureEvent* event) {
   DCHECK(window_->IsVisible());
-  return delegate_->OnGestureEvent(event);
+  delegate_->OnGestureEvent(event);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/ui/views/widget/native_widget_aura.h b/ui/views/widget/native_widget_aura.h
index 623e9b8..7a7474e 100644
--- a/ui/views/widget/native_widget_aura.h
+++ b/ui/views/widget/native_widget_aura.h
@@ -157,7 +157,7 @@ class VIEWS_EXPORT NativeWidgetAura : public internal::NativeWidgetPrivate,
   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;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::client::ActivationDelegate:
   virtual bool ShouldActivate() const OVERRIDE;
diff --git a/ui/views/widget/native_widget_aura_unittest.cc b/ui/views/widget/native_widget_aura_unittest.cc
index f0db7c2..7e06b79 100644
--- a/ui/views/widget/native_widget_aura_unittest.cc
+++ b/ui/views/widget/native_widget_aura_unittest.cc
@@ -216,9 +216,10 @@ class GestureTrackingView : public views::View {
   }
 
   // View overrides:
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
     got_gesture_event_ = true;
-    return consume_gesture_event_ ? ui::ER_CONSUMED : ui::ER_UNHANDLED;
+    if (consume_gesture_event_)
+      event->StopPropagation();
   }
 
  private:
diff --git a/ui/views/widget/native_widget_delegate.h b/ui/views/widget/native_widget_delegate.h
index 29ab54f..bc82cdc 100644
--- a/ui/views/widget/native_widget_delegate.h
+++ b/ui/views/widget/native_widget_delegate.h
@@ -112,7 +112,7 @@ class VIEWS_EXPORT NativeWidgetDelegate {
 
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) = 0;
   virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) = 0;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) = 0;
+  virtual void OnGestureEvent(ui::GestureEvent* event) = 0;
 
   // Runs the specified native command. Returns true if the command is handled.
   virtual bool ExecuteCommand(int command_id) = 0;
diff --git a/ui/views/widget/root_view.cc b/ui/views/widget/root_view.cc
index 4dc3980..3593424 100644
--- a/ui/views/widget/root_view.cc
+++ b/ui/views/widget/root_view.cc
@@ -196,9 +196,7 @@ ui::EventResult RootView::DispatchTouchEvent(ui::TouchEvent* event) {
   return status;
 }
 
-ui::EventResult RootView::DispatchGestureEvent(ui::GestureEvent* event) {
-  ui::EventResult status = ui::ER_UNHANDLED;
-
+void RootView::DispatchGestureEvent(ui::GestureEvent* event) {
   if (gesture_handler_) {
     // |gesture_handler_| (or |scroll_gesture_handler_|) can be deleted during
     // processing.
@@ -206,8 +204,7 @@ ui::EventResult RootView::DispatchGestureEvent(ui::GestureEvent* event) {
         (event->IsScrollGestureEvent() || event->IsFlingScrollEvent())  ?
             scroll_gesture_handler_ : gesture_handler_;
     ui::GestureEvent handler_event(*event, static_cast<View*>(this), handler);
-
-    ui::EventResult status = handler->ProcessGestureEvent(&handler_event);
+    handler->ProcessGestureEvent(&handler_event);
 
     if (event->type() == ui::ET_GESTURE_END &&
         event->details().touch_points() <= 1) {
@@ -225,10 +222,13 @@ ui::EventResult RootView::DispatchGestureEvent(ui::GestureEvent* event) {
       scroll_gesture_handler_ = NULL;
     }
 
-    if (status == ui::ER_CONSUMED)
-      return status;
-
-    DCHECK_EQ(ui::ER_UNHANDLED, status);
+    if (handler_event.stopped_propagation()) {
+      event->StopPropagation();
+      return;
+    } else if (handler_event.handled()) {
+      event->SetHandled();
+      return;
+    }
 
     if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN &&
         !scroll_gesture_handler_) {
@@ -241,14 +241,19 @@ ui::EventResult RootView::DispatchGestureEvent(ui::GestureEvent* event) {
           scroll_gesture_handler_ = scroll_gesture_handler_->parent()) {
         ui::GestureEvent gesture_event(*event, static_cast<View*>(this),
                                        scroll_gesture_handler_);
-        status = scroll_gesture_handler_->ProcessGestureEvent(&gesture_event);
-        if (status == ui::ER_CONSUMED)
-          return status;
+        scroll_gesture_handler_->ProcessGestureEvent(&gesture_event);
+        if (gesture_event.stopped_propagation()) {
+          event->StopPropagation();
+          return;
+        } else if (gesture_event.handled()) {
+          event->SetHandled();
+          return;
+        }
       }
       scroll_gesture_handler_ = NULL;
     }
 
-    return ui::ER_UNHANDLED;
+    return;
   }
 
   // Walk up the tree until we find a view that wants the gesture event.
@@ -257,34 +262,35 @@ ui::EventResult RootView::DispatchGestureEvent(ui::GestureEvent* event) {
       gesture_handler_ = gesture_handler_->parent()) {
     if (!gesture_handler_->enabled()) {
       // Disabled views eat events but are treated as not handled.
-      return ui::ER_UNHANDLED;
+      return;
     }
 
     // See if this view wants to handle the Gesture.
     ui::GestureEvent gesture_event(*event, static_cast<View*>(this),
                                    gesture_handler_);
-    status = gesture_handler_->ProcessGestureEvent(&gesture_event);
+    gesture_handler_->ProcessGestureEvent(&gesture_event);
 
     // The view could have removed itself from the tree when handling
     // OnGestureEvent(). So handle as per OnMousePressed. NB: we
     // assume that the RootView itself cannot be so removed.
     if (!gesture_handler_)
-      return ui::ER_UNHANDLED;
+      return;
 
-    if (status == ui::ER_CONSUMED) {
+    if (gesture_event.handled()) {
       if (gesture_event.type() == ui::ET_GESTURE_SCROLL_BEGIN)
         scroll_gesture_handler_ = gesture_handler_;
-      return status;
+      if (gesture_event.stopped_propagation())
+        event->StopPropagation();
+      else
+        event->SetHandled();
+      return;
     }
 
     // The gesture event wasn't processed. Go up the view hierarchy and
     // dispatch the gesture event.
-    DCHECK_EQ(ui::ER_UNHANDLED, status);
   }
 
   gesture_handler_ = NULL;
-
-  return status;
 }
 
 // Focus -----------------------------------------------------------------------
diff --git a/ui/views/widget/root_view.h b/ui/views/widget/root_view.h
index 66ff49b..c87692d 100644
--- a/ui/views/widget/root_view.h
+++ b/ui/views/widget/root_view.h
@@ -64,7 +64,7 @@ class VIEWS_EXPORT RootView : public View, public FocusTraversable {
   ui::EventResult DispatchKeyEvent(const ui::KeyEvent& event);
   ui::EventResult DispatchScrollEvent(ui::ScrollEvent* event);
   ui::EventResult DispatchTouchEvent(ui::TouchEvent* event);
-  virtual ui::EventResult DispatchGestureEvent(ui::GestureEvent* event);
+  virtual void DispatchGestureEvent(ui::GestureEvent* event);
 
   // Focus ---------------------------------------------------------------------
 
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 9942c3d..457e1fe 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -1170,7 +1170,7 @@ ui::EventResult Widget::OnScrollEvent(ui::ScrollEvent* event) {
       DispatchScrollEvent(event);
 }
 
-ui::EventResult Widget::OnGestureEvent(ui::GestureEvent* event) {
+void Widget::OnGestureEvent(ui::GestureEvent* event) {
   ScopedEvent scoped(this, *event);
   switch (event->type()) {
     case ui::ET_GESTURE_TAP_DOWN:
@@ -1191,8 +1191,7 @@ ui::EventResult Widget::OnGestureEvent(ui::GestureEvent* event) {
     default:
       break;
   }
-  return static_cast<internal::RootView*>(GetRootView())->
-      DispatchGestureEvent(event);
+  static_cast<internal::RootView*>(GetRootView())->DispatchGestureEvent(event);
 }
 
 bool Widget::ExecuteCommand(int command_id) {
diff --git a/ui/views/widget/widget.h b/ui/views/widget/widget.h
index 139c69a..3daac12 100644
--- a/ui/views/widget/widget.h
+++ b/ui/views/widget/widget.h
@@ -659,7 +659,7 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   virtual void OnMouseCaptureLost() OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
   virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
   virtual bool ExecuteCommand(int command_id) OVERRIDE;
   virtual InputMethod* GetInputMethodDirect() OVERRIDE;
   virtual const std::vector<ui::Layer*>& GetRootLayers() OVERRIDE;
diff --git a/ui/views/widget/widget_unittest.cc b/ui/views/widget/widget_unittest.cc
index 44fa495..f4d9381 100644
--- a/ui/views/widget/widget_unittest.cc
+++ b/ui/views/widget/widget_unittest.cc
@@ -127,12 +127,11 @@ class GestureCaptureView : public View {
 
  private:
   // Overridden from View:
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
     if (event->type() == ui::ET_GESTURE_BEGIN) {
       GetWidget()->SetCapture(this);
-      return ui::ER_CONSUMED;
+      event->StopPropagation();
     }
-    return ui::ER_UNHANDLED;
   }
 
   DISALLOW_COPY_AND_ASSIGN(GestureCaptureView);