Use the CHECK'd AsXXXEvent() methods on Event rather than the unsafe static_cast's.

Review-Url: https://codereview.chromium.org/2374213003
Cr-Commit-Position: refs/heads/master@{#422830}

ui/events/event.cc

@@ -288,6 +288,16 @@ bool Event::IsTouchPointerEvent() const {
              EventPointerType::POINTER_TYPE_TOUCH;
 }
 
+CancelModeEvent* Event::AsCancelModeEvent() {
+  CHECK(IsCancelModeEvent());
+  return static_cast<CancelModeEvent*>(this);
+}
+
+const CancelModeEvent* Event::AsCancelModeEvent() const {
+  CHECK(IsCancelModeEvent());
+  return static_cast<const CancelModeEvent*>(this);
+}
+
 GestureEvent* Event::AsGestureEvent() {
   CHECK(IsGestureEvent());
   return static_cast<GestureEvent*>(this);

ui/events/event.h

@@ -30,6 +30,7 @@ class Transform;
 }
 
 namespace ui {
+class CancelModeEvent;
 class EventTarget;
 class KeyEvent;
 class LocatedEvent;
@@ -107,6 +108,10 @@ class EVENTS_EXPORT Event {
   bool IsAltGrDown() const { return (flags_ & EF_ALTGR_DOWN) != 0; }
   bool IsCapsLockOn() const { return (flags_ & EF_CAPS_LOCK_ON) != 0; }
 
+  bool IsCancelModeEvent() const {
+    return type_ == ET_CANCEL_MODE;
+  }
+
   bool IsKeyEvent() const {
     return type_ == ET_KEY_PRESSED || type_ == ET_KEY_RELEASED;
   }
@@ -220,6 +225,12 @@ class EVENTS_EXPORT Event {
            IsGestureEvent() || IsPointerEvent();
   }
 
+  // Convenience methods to cast |this| to a CancelModeEvent.
+  // IsCancelModeEvent() must be true as a precondition to calling these
+  // methods.
+  CancelModeEvent* AsCancelModeEvent();
+  const CancelModeEvent* AsCancelModeEvent() const;
+
   // Convenience methods to cast |this| to a GestureEvent. IsGestureEvent()
   // must be true as a precondition to calling these methods.
   GestureEvent* AsGestureEvent();

ui/events/event_handler.cc

@@ -21,20 +21,18 @@ EventHandler::~EventHandler() {
 }
 
 void EventHandler::OnEvent(Event* event) {
-  // TODO(tdanderson): Encapsulate static_casts in ui::Event for all
-  //                   event types.
   if (event->IsKeyEvent())
-    OnKeyEvent(static_cast<KeyEvent*>(event));
+    OnKeyEvent(event->AsKeyEvent());
   else if (event->IsMouseEvent())
-    OnMouseEvent(static_cast<MouseEvent*>(event));
+    OnMouseEvent(event->AsMouseEvent());
   else if (event->IsScrollEvent())
-    OnScrollEvent(static_cast<ScrollEvent*>(event));
+    OnScrollEvent(event->AsScrollEvent());
   else if (event->IsTouchEvent())
-    OnTouchEvent(static_cast<TouchEvent*>(event));
+    OnTouchEvent(event->AsTouchEvent());
   else if (event->IsGestureEvent())
     OnGestureEvent(event->AsGestureEvent());
-  else if (event->type() == ET_CANCEL_MODE)
-    OnCancelMode(static_cast<CancelModeEvent*>(event));
+  else if (event->IsCancelModeEvent())
+    OnCancelMode(event->AsCancelModeEvent());
 }
 
 void EventHandler::OnKeyEvent(KeyEvent* event) {

ui/events/ozone/evdev/input_injector_evdev_unittest.cc

@@ -32,9 +32,9 @@ class EventObserver {
   void OnEvent(Event* event) {
     if (event->IsMouseEvent()) {
       if (event->type() == ET_MOUSEWHEEL) {
-        OnMouseWheelEvent(static_cast<MouseWheelEvent*>(event));
+        OnMouseWheelEvent(event->AsMouseWheelEvent());
       } else {
-        OnMouseEvent(static_cast<MouseEvent*>(event));
+        OnMouseEvent(event->AsMouseEvent());
       }
     }
   }

ui/ozone/platform/drm/host/drm_window_host.cc

@@ -160,7 +160,7 @@ bool DrmWindowHost::CanDispatchEvent(const PlatformEvent& ne) {
                              snapshot->current_mode()->size());
     return display_bounds == bounds_;
   } else if (event->IsLocatedEvent()) {
-    LocatedEvent* located_event = static_cast<LocatedEvent*>(event);
+    LocatedEvent* located_event = event->AsLocatedEvent();
     return bounds_.Contains(located_event->location());
   }
 
@@ -174,7 +174,7 @@ uint32_t DrmWindowHost::DispatchEvent(const PlatformEvent& native_event) {
   Event* event = static_cast<Event*>(native_event);
   if (event->IsLocatedEvent()) {
     // Make the event location relative to this window's origin.
-    LocatedEvent* located_event = static_cast<LocatedEvent*>(event);
+    LocatedEvent* located_event = event->AsLocatedEvent();
     gfx::PointF location = located_event->location_f();
     location -= gfx::Vector2dF(bounds_.OffsetFromOrigin());
     located_event->set_location_f(location);

ui/ozone/platform/wayland/wayland_pointer_unittest.cc

@@ -86,7 +86,7 @@ TEST_F(WaylandPointerTest, Motion) {
 
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseEvent());
-  auto mouse_event = static_cast<MouseEvent*>(event.get());
+  auto mouse_event = event->AsMouseEvent();
   EXPECT_EQ(ET_MOUSE_MOVED, mouse_event->type());
   EXPECT_EQ(0, mouse_event->button_flags());
   EXPECT_EQ(0, mouse_event->changed_button_flags());
@@ -112,7 +112,7 @@ TEST_F(WaylandPointerTest, MotionDragged) {
 
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseEvent());
-  auto mouse_event = static_cast<MouseEvent*>(event.get());
+  auto mouse_event = event->AsMouseEvent();
   EXPECT_EQ(ET_MOUSE_DRAGGED, mouse_event->type());
   EXPECT_EQ(EF_MIDDLE_MOUSE_BUTTON, mouse_event->button_flags());
   EXPECT_EQ(0, mouse_event->changed_button_flags());
@@ -137,7 +137,7 @@ TEST_F(WaylandPointerTest, ButtonPress) {
 
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseEvent());
-  auto mouse_event = static_cast<MouseEvent*>(event.get());
+  auto mouse_event = event->AsMouseEvent();
   EXPECT_EQ(ET_MOUSE_PRESSED, mouse_event->type());
   EXPECT_EQ(EF_LEFT_MOUSE_BUTTON | EF_RIGHT_MOUSE_BUTTON,
             mouse_event->button_flags());
@@ -165,7 +165,7 @@ TEST_F(WaylandPointerTest, ButtonRelease) {
 
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseEvent());
-  auto mouse_event = static_cast<MouseEvent*>(event.get());
+  auto mouse_event = event->AsMouseEvent();
   EXPECT_EQ(ET_MOUSE_RELEASED, mouse_event->type());
   EXPECT_EQ(EF_LEFT_MOUSE_BUTTON | EF_BACK_MOUSE_BUTTON,
             mouse_event->button_flags());
@@ -192,7 +192,7 @@ TEST_F(WaylandPointerTest, AxisVertical) {
 
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseWheelEvent());
-  auto mouse_wheel_event = static_cast<MouseWheelEvent*>(event.get());
+  auto mouse_wheel_event = event->AsMouseWheelEvent();
   EXPECT_EQ(gfx::Vector2d(0, -2 * MouseWheelEvent::kWheelDelta),
             mouse_wheel_event->offset());
   EXPECT_EQ(EF_RIGHT_MOUSE_BUTTON, mouse_wheel_event->button_flags());
@@ -220,7 +220,7 @@ TEST_F(WaylandPointerTest, AxisHorizontal) {
 
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseWheelEvent());
-  auto mouse_wheel_event = static_cast<MouseWheelEvent*>(event.get());
+  auto mouse_wheel_event = event->AsMouseWheelEvent();
   EXPECT_EQ(gfx::Vector2d(MouseWheelEvent::kWheelDelta, 0),
             mouse_wheel_event->offset());
   EXPECT_EQ(EF_LEFT_MOUSE_BUTTON, mouse_wheel_event->button_flags());

ui/ozone/platform/wayland/wayland_window_unittest.cc

@@ -94,7 +94,7 @@ TEST_F(WaylandWindowTest, DispatchEvent) {
   window.DispatchEvent(&test_mouse_event);
   ASSERT_TRUE(event);
   ASSERT_TRUE(event->IsMouseEvent());
-  auto mouse_event = static_cast<MouseEvent*>(event.get());
+  auto mouse_event = event->AsMouseEvent();
   EXPECT_EQ(mouse_event->location_f(), test_mouse_event.location_f());
   EXPECT_EQ(mouse_event->root_location_f(), test_mouse_event.root_location_f());
   EXPECT_EQ(mouse_event->time_stamp(), test_mouse_event.time_stamp());