Explicit interface for synchronous InputHandlerProxy input handling

content/renderer/gpu/input_handler_proxy.cc

 // 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.
 
 #include "content/renderer/gpu/input_handler_proxy.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "content/renderer/gpu/input_handler_proxy_client.h"
 #include "third_party/WebKit/public/platform/Platform.h"
@@ skipping 28 matching lines @@
   input_handler_ = NULL;
   DCHECK(client_);
   client_->WillShutdown();
 }
 
 void InputHandlerProxy::SetClient(InputHandlerProxyClient* client) {
   DCHECK(!client_ || !client);
   client_ = client;
 }
 
-void InputHandlerProxy::HandleInputEvent(const WebInputEvent& event) {
+InputHandlerProxy::EventDisposition InputHandlerProxy::HandleInputEvent(
+    const WebInputEvent& event) {
   DCHECK(client_);
   DCHECK(input_handler_);
 
   InputHandlerProxy::EventDisposition disposition =
       HandleInputEventInternal(event);
-  switch (disposition) {
-    case DidHandle:
-      client_->DidHandleInputEvent();
-      break;
-    case DidNotHandle:
-      client_->DidNotHandleInputEvent(true /* send_to_widget */);
-      break;
-    case DropEvent:
-      client_->DidNotHandleInputEvent(false /* send_to_widget */);
-      break;
-  }
   if (event.modifiers & WebInputEvent::IsLastInputEventForCurrentVSync) {
     input_handler_->DidReceiveLastInputEventForBeginFrame(
         base::TimeTicks::FromInternalValue(event.timeStampSeconds *
                                            base::Time::kMicrosecondsPerSecond));
   }
+  return disposition;
 }
 
 InputHandlerProxy::EventDisposition
 InputHandlerProxy::HandleInputEventInternal(const WebInputEvent& event) {
   if (event.type == WebInputEvent::MouseWheel) {
     const WebMouseWheelEvent& wheel_event =
         *static_cast<const WebMouseWheelEvent*>(&event);
     if (wheel_event.scrollByPage) {
       // TODO(jamesr): We don't properly handle scroll by page in the compositor
       // thread, so punt it to the main thread. http://crbug.com/236639
-      return DidNotHandle;
+      return EVENT_DISPOSITION_DID_NOT_HANDLE;
     }
     cc::InputHandler::ScrollStatus scroll_status = input_handler_->ScrollBegin(
         gfx::Point(wheel_event.x, wheel_event.y), cc::InputHandler::Wheel);
     switch (scroll_status) {
       case cc::InputHandler::ScrollStarted: {
         TRACE_EVENT_INSTANT2(
             "renderer",
             "InputHandlerProxy::handle_input wheel scroll",
             TRACE_EVENT_SCOPE_THREAD,
             "deltaX",
             -wheel_event.deltaX,
             "deltaY",
             -wheel_event.deltaY);
         bool did_scroll = input_handler_->ScrollBy(
             gfx::Point(wheel_event.x, wheel_event.y),
             gfx::Vector2dF(-wheel_event.deltaX, -wheel_event.deltaY));
         input_handler_->ScrollEnd();
-        return did_scroll ? DidHandle : DropEvent;
+        return did_scroll ? EVENT_DISPOSITION_DID_HANDLE
+                          : EVENT_DISPOSITION_DROP_EVENT;
       }
       case cc::InputHandler::ScrollIgnored:
-        // TODO(jamesr): This should be DropEvent, but in cases where we fail to
-        // properly sync scrollability it's safer to send the
-        // event to the main thread. Change back to DropEvent once we have
-        // synchronization bugs sorted out.
-        return DidNotHandle;
+        // TODO(jamesr): This should be EVENT_DISPOSITION_DROP_EVENT, but in
+        // cases where we fail to properly sync scrollability it's safer to send
+        // the event to the main thread. Change back to
+        // EVENT_DISPOSITION_DROP_EVENT once we have synchronization bugs sorted
+        // out.
+        return EVENT_DISPOSITION_DID_NOT_HANDLE;
       case cc::InputHandler::ScrollOnMainThread:
-        return DidNotHandle;
+        return EVENT_DISPOSITION_DID_NOT_HANDLE;
     }
   } else if (event.type == WebInputEvent::GestureScrollBegin) {
     DCHECK(!gesture_scroll_on_impl_thread_);
 #ifndef NDEBUG
     DCHECK(!expect_scroll_update_end_);
     expect_scroll_update_end_ = true;
 #endif
     const WebGestureEvent& gesture_event =
         *static_cast<const WebGestureEvent*>(&event);
     cc::InputHandler::ScrollStatus scroll_status = input_handler_->ScrollBegin(
         gfx::Point(gesture_event.x, gesture_event.y),
         cc::InputHandler::Gesture);
     switch (scroll_status) {
       case cc::InputHandler::ScrollStarted:
         gesture_scroll_on_impl_thread_ = true;
-        return DidHandle;
+        return EVENT_DISPOSITION_DID_HANDLE;
       case cc::InputHandler::ScrollOnMainThread:
-        return DidNotHandle;
+        return EVENT_DISPOSITION_DID_NOT_HANDLE;
       case cc::InputHandler::ScrollIgnored:
-        return DropEvent;
+        return EVENT_DISPOSITION_DROP_EVENT;
     }
   } else if (event.type == WebInputEvent::GestureScrollUpdate) {
 #ifndef NDEBUG
     DCHECK(expect_scroll_update_end_);
 #endif
 
     if (!gesture_scroll_on_impl_thread_ && !gesture_pinch_on_impl_thread_)
-      return DidNotHandle;
+      return EVENT_DISPOSITION_DID_NOT_HANDLE;
 
     const WebGestureEvent& gesture_event =
         *static_cast<const WebGestureEvent*>(&event);
     bool did_scroll = input_handler_->ScrollBy(
         gfx::Point(gesture_event.x, gesture_event.y),
         gfx::Vector2dF(-gesture_event.data.scrollUpdate.deltaX,
                        -gesture_event.data.scrollUpdate.deltaY));
-    return did_scroll ? DidHandle : DropEvent;
+    return did_scroll ? EVENT_DISPOSITION_DID_HANDLE
+                      : EVENT_DISPOSITION_DROP_EVENT;
   } else if (event.type == WebInputEvent::GestureScrollEnd) {
 #ifndef NDEBUG
     DCHECK(expect_scroll_update_end_);
     expect_scroll_update_end_ = false;
 #endif
     if (!gesture_scroll_on_impl_thread_)
-      return DidNotHandle;
+      return EVENT_DISPOSITION_DID_NOT_HANDLE;
 
     input_handler_->ScrollEnd();
     gesture_scroll_on_impl_thread_ = false;
-    return DidHandle;
+    return EVENT_DISPOSITION_DID_HANDLE;
   } else if (event.type == WebInputEvent::GesturePinchBegin) {
 #ifndef NDEBUG
     DCHECK(!expect_pinch_update_end_);
     expect_pinch_update_end_ = true;
 #endif
     input_handler_->PinchGestureBegin();
     gesture_pinch_on_impl_thread_ = true;
-    return DidHandle;
+    return EVENT_DISPOSITION_DID_HANDLE;
   } else if (event.type == WebInputEvent::GesturePinchEnd) {
 #ifndef NDEBUG
     DCHECK(expect_pinch_update_end_);
     expect_pinch_update_end_ = false;
 #endif
     gesture_pinch_on_impl_thread_ = false;
     input_handler_->PinchGestureEnd();
-    return DidHandle;
+    return EVENT_DISPOSITION_DID_HANDLE;
   } else if (event.type == WebInputEvent::GesturePinchUpdate) {
 #ifndef NDEBUG
     DCHECK(expect_pinch_update_end_);
 #endif
     const WebGestureEvent& gesture_event =
         *static_cast<const WebGestureEvent*>(&event);
     input_handler_->PinchGestureUpdate(
         gesture_event.data.pinchUpdate.scale,
         gfx::Point(gesture_event.x, gesture_event.y));
-    return DidHandle;
+    return EVENT_DISPOSITION_DID_HANDLE;
   } else if (event.type == WebInputEvent::GestureFlingStart) {
     const WebGestureEvent& gesture_event =
         *static_cast<const WebGestureEvent*>(&event);
     return HandleGestureFling(gesture_event);
   } else if (event.type == WebInputEvent::GestureFlingCancel) {
     if (CancelCurrentFling())
-      return DidHandle;
+      return EVENT_DISPOSITION_DID_HANDLE;
     else if (!fling_may_be_active_on_main_thread_)
-      return DropEvent;
+      return EVENT_DISPOSITION_DROP_EVENT;
   } else if (event.type == WebInputEvent::TouchStart) {
     const WebTouchEvent& touch_event =
         *static_cast<const WebTouchEvent*>(&event);
     if (!input_handler_->HaveTouchEventHandlersAt(touch_event.touches[0]
                                                       .position))
-      return DropEvent;
+      return EVENT_DISPOSITION_DROP_EVENT;
   } else if (WebInputEvent::isKeyboardEventType(event.type)) {
     CancelCurrentFling();
   }
 
-  return DidNotHandle;
+  return EVENT_DISPOSITION_DID_NOT_HANDLE;
 }
 
 InputHandlerProxy::EventDisposition
 InputHandlerProxy::HandleGestureFling(
     const WebGestureEvent& gesture_event) {
   cc::InputHandler::ScrollStatus scroll_status;
 
   if (gesture_event.sourceDevice == WebGestureEvent::Touchpad) {
     scroll_status = input_handler_->ScrollBegin(
         gfx::Point(gesture_event.x, gesture_event.y),
@@ skipping 25 matching lines @@
           this);
       fling_parameters_.delta =
           WebFloatPoint(gesture_event.data.flingStart.velocityX,
                         gesture_event.data.flingStart.velocityY);
       fling_parameters_.point = WebPoint(gesture_event.x, gesture_event.y);
       fling_parameters_.globalPoint =
           WebPoint(gesture_event.globalX, gesture_event.globalY);
       fling_parameters_.modifiers = gesture_event.modifiers;
       fling_parameters_.sourceDevice = gesture_event.sourceDevice;
       input_handler_->ScheduleAnimation();
-      return DidHandle;
+      return EVENT_DISPOSITION_DID_HANDLE;
     }
     case cc::InputHandler::ScrollOnMainThread: {
       TRACE_EVENT_INSTANT0("renderer",
                            "InputHandlerProxy::HandleGestureFling::"
                            "scroll_on_main_thread",
                            TRACE_EVENT_SCOPE_THREAD);
       fling_may_be_active_on_main_thread_ = true;
-      return DidNotHandle;
+      return EVENT_DISPOSITION_DID_NOT_HANDLE;
     }
     case cc::InputHandler::ScrollIgnored: {
       TRACE_EVENT_INSTANT0(
           "renderer",
           "InputHandlerProxy::HandleGestureFling::ignored",
           TRACE_EVENT_SCOPE_THREAD);
       if (gesture_event.sourceDevice == WebGestureEvent::Touchpad) {
         // We still pass the curve to the main thread if there's nothing
         // scrollable, in case something
         // registers a handler before the curve is over.
-        return DidNotHandle;
+        return EVENT_DISPOSITION_DID_NOT_HANDLE;
       }
-      return DropEvent;
+      return EVENT_DISPOSITION_DROP_EVENT;
     }
   }
-  return DidNotHandle;
+  return EVENT_DISPOSITION_DID_NOT_HANDLE;
 }
 
 void InputHandlerProxy::Animate(base::TimeTicks time) {
   if (!fling_curve_)
     return;
 
   double monotonic_time_sec = (time - base::TimeTicks()).InSecondsF();
   if (!fling_parameters_.startTime) {
     fling_parameters_.startTime = monotonic_time_sec;
     input_handler_->ScheduleAnimation();
@@ skipping 52 matching lines @@
   synthetic_wheel.hasPreciseScrollingDeltas = true;
   synthetic_wheel.x = fling_parameters_.point.x;
   synthetic_wheel.y = fling_parameters_.point.y;
   synthetic_wheel.globalX = fling_parameters_.globalPoint.x;
   synthetic_wheel.globalY = fling_parameters_.globalPoint.y;
   synthetic_wheel.modifiers = fling_parameters_.modifiers;
 
   InputHandlerProxy::EventDisposition disposition =
       HandleInputEventInternal(synthetic_wheel);
   switch (disposition) {
-    case DidHandle:
+    case EVENT_DISPOSITION_DID_HANDLE:
       return true;
-    case DropEvent:
+    case EVENT_DISPOSITION_DROP_EVENT:
       break;
-    case DidNotHandle:
+    case EVENT_DISPOSITION_DID_NOT_HANDLE:
       TRACE_EVENT_INSTANT0("renderer",
                            "InputHandlerProxy::scrollBy::AbortFling",
                            TRACE_EVENT_SCOPE_THREAD);
-      // If we got a DidNotHandle, that means we need to deliver wheels on the
-      // main thread. In this case we need to schedule a commit and transfer the
-      // fling curve over to the main thread and run the rest of the wheels from
-      // there. This can happen when flinging a page that contains a scrollable
-      // subarea that we can't scroll on the thread if the fling starts outside
-      // the subarea but then is flung "under" the pointer.
+      // If we got a EVENT_DISPOSITION_DID_NOT_HANDLE, that means we need to
+      // deliver wheels on the main thread. In this case we need to schedule a
+      // commit and transfer the fling curve over to the main thread and run the
+      // rest of the wheels from there. This can happen when flinging a page
+      // that contains a scrollable subarea that we can't scroll on the thread
+      // if the fling starts outside the subarea but then is flung "under" the
+      // pointer.
       client_->TransferActiveWheelFlingAnimation(fling_parameters_);
       fling_may_be_active_on_main_thread_ = true;
       CancelCurrentFling();
       break;
   }
 
   return false;
 }
 
 static gfx::Vector2dF ToClientScrollIncrement(const WebFloatSize& increment) {
@@ skipping 34 matching lines @@
   TRACE_EVENT2("renderer",
                "InputHandlerProxy::notifyCurrentFlingVelocity",
                "vx",
                velocity.width,
                "vy",
                velocity.height);
   input_handler_->NotifyCurrentFlingVelocity(ToClientScrollIncrement(velocity));
 }
 
 }  // namespace content