[NOT FOR REVIEW] Patch demonstrating the changes required for browser side fling.

content/renderer/gpu/input_handler_proxy.cc

Index: content/renderer/gpu/input_handler_proxy.cc
diff --git a/content/renderer/gpu/input_handler_proxy.cc b/content/renderer/gpu/input_handler_proxy.cc
index 77dd0f0af8472559f704120c5ad6618f4c2ec418..7dcf656bbd2569c7a6d75851c6a0d751c6b8c00c 100644
--- a/content/renderer/gpu/input_handler_proxy.cc
+++ b/content/renderer/gpu/input_handler_proxy.cc
@@ -8,7 +8,7 @@
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "content/renderer/gpu/input_handler_proxy_client.h"
-#include "third_party/WebKit/public/platform/Platform.h"
+#include "third_party/WebKit/public/platform/WebFloatSize.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/latency_info.h"
 
@@ -60,10 +60,7 @@ InputHandlerProxy::InputHandlerProxy(cc::InputHandler* input_handler)
       expect_pinch_update_end_(false),
 #endif
       gesture_scroll_on_impl_thread_(false),
-      gesture_pinch_on_impl_thread_(false),
-      fling_may_be_active_on_main_thread_(false),
-      fling_overscrolled_horizontally_(false),
-      fling_overscrolled_vertically_(false) {
+      gesture_pinch_on_impl_thread_(false) {
   input_handler_->BindToClient(this);
 }
 
@@ -208,22 +205,15 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleInputEvent(
         gfx::Point(gesture_event.x, gesture_event.y));
     return DID_HANDLE;
   } else if (event.type == WebInputEvent::GestureFlingStart) {
-    const WebGestureEvent& gesture_event =
-        *static_cast<const WebGestureEvent*>(&event);
-    return HandleGestureFling(gesture_event);
+    NOTREACHED();

[jamesr, 2013/11/27 03:11:27]

you still have to hit test in order to bind to the correct layer for the fling,
don't you?

   } else if (event.type == WebInputEvent::GestureFlingCancel) {
-    if (CancelCurrentFling())
-      return DID_HANDLE;
-    else if (!fling_may_be_active_on_main_thread_)
-      return DROP_EVENT;
+    NOTREACHED();
   } 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 DROP_EVENT;
-  } else if (WebInputEvent::isKeyboardEventType(event.type)) {
-    CancelCurrentFling();
   } else if (event.type == WebInputEvent::MouseMove) {
     const WebMouseEvent& mouse_event =
         *static_cast<const WebMouseEvent*>(&event);
@@ -234,229 +224,12 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleInputEvent(
   return 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),
-        cc::InputHandler::NonBubblingGesture);
-  } else {
-    if (!gesture_scroll_on_impl_thread_)
-      scroll_status = cc::InputHandler::ScrollOnMainThread;
-    else
-      scroll_status = input_handler_->FlingScrollBegin();
-  }
-
-#ifndef NDEBUG
-  expect_scroll_update_end_ = false;
-#endif
-
-  switch (scroll_status) {
-    case cc::InputHandler::ScrollStarted: {
-      if (gesture_event.sourceDevice == WebGestureEvent::Touchpad)
-        input_handler_->ScrollEnd();
-
-      fling_curve_.reset(client_->CreateFlingAnimationCurve(
-          gesture_event.sourceDevice,
-          WebFloatPoint(gesture_event.data.flingStart.velocityX,
-                        gesture_event.data.flingStart.velocityY),
-          WebKit::WebSize()));
-      fling_overscrolled_horizontally_ = false;
-      fling_overscrolled_vertically_ = false;
-      TRACE_EVENT_ASYNC_BEGIN0(
-          "renderer",
-          "InputHandlerProxy::HandleGestureFling::started",
-          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 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 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 DID_NOT_HANDLE;
-      }
-      return DROP_EVENT;
-    }
-  }
-  return 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();
-    return;
-  }
-
-  if (fling_curve_->apply(monotonic_time_sec - fling_parameters_.startTime,
-                          this)) {
-    input_handler_->ScheduleAnimation();
-  } else {
-    TRACE_EVENT_INSTANT0("renderer",
-                         "InputHandlerProxy::animate::flingOver",
-                         TRACE_EVENT_SCOPE_THREAD);
-    CancelCurrentFling();
-  }
-}
-
-void InputHandlerProxy::MainThreadHasStoppedFlinging() {
-  fling_may_be_active_on_main_thread_ = false;
 }
 
 void InputHandlerProxy::DidOverscroll(const cc::DidOverscrollParams& params) {
   DCHECK(client_);
-  if (fling_curve_) {
-    static const int kFlingOverscrollThreshold = 1;
-    fling_overscrolled_horizontally_ |=
-        std::abs(params.accumulated_overscroll.x()) >=
-        kFlingOverscrollThreshold;
-    fling_overscrolled_vertically_ |=
-        std::abs(params.accumulated_overscroll.y()) >=
-        kFlingOverscrollThreshold;
-  }
-
   client_->DidOverscroll(params);
 }
 
-bool InputHandlerProxy::CancelCurrentFling() {
-  bool had_fling_animation = fling_curve_;
-  if (had_fling_animation &&
-      fling_parameters_.sourceDevice == WebGestureEvent::Touchscreen) {
-    input_handler_->ScrollEnd();
-    TRACE_EVENT_ASYNC_END0(
-        "renderer",
-        "InputHandlerProxy::HandleGestureFling::started",
-        this);
-  }
-
-  TRACE_EVENT_INSTANT1("renderer",
-                       "InputHandlerProxy::CancelCurrentFling",
-                       TRACE_EVENT_SCOPE_THREAD,
-                       "had_fling_animation",
-                       had_fling_animation);
-  fling_curve_.reset();
-  gesture_scroll_on_impl_thread_ = false;
-  fling_parameters_ = WebKit::WebActiveWheelFlingParameters();
-  return had_fling_animation;
-}
-
-bool InputHandlerProxy::TouchpadFlingScroll(
-    const WebFloatSize& increment) {
-  WebMouseWheelEvent synthetic_wheel;
-  synthetic_wheel.type = WebInputEvent::MouseWheel;
-  synthetic_wheel.deltaX = increment.width;
-  synthetic_wheel.deltaY = increment.height;
-  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 =
-      HandleInputEvent(synthetic_wheel);
-  switch (disposition) {
-    case DID_HANDLE:
-      return true;
-    case DROP_EVENT:
-      break;
-    case DID_NOT_HANDLE:
-      TRACE_EVENT_INSTANT0("renderer",
-                           "InputHandlerProxy::scrollBy::AbortFling",
-                           TRACE_EVENT_SCOPE_THREAD);
-      // If we got a 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) {
-  return gfx::Vector2dF(-increment.width, -increment.height);
-}
-
-void InputHandlerProxy::scrollBy(const WebFloatSize& increment) {
-  WebFloatSize clipped_increment;
-  if (!fling_overscrolled_horizontally_)
-    clipped_increment.width = increment.width;
-  if (!fling_overscrolled_vertically_)
-    clipped_increment.height = increment.height;
-
-  if (clipped_increment == WebFloatSize())
-    return;
-
-  TRACE_EVENT2("renderer",
-               "InputHandlerProxy::scrollBy",
-               "x",
-               clipped_increment.width,
-               "y",
-               clipped_increment.height);
-
-  bool did_scroll = false;
-
-  switch (fling_parameters_.sourceDevice) {
-    case WebGestureEvent::Touchpad:
-      did_scroll = TouchpadFlingScroll(clipped_increment);
-      break;
-    case WebGestureEvent::Touchscreen:
-      clipped_increment = ToClientScrollIncrement(clipped_increment);
-      did_scroll = input_handler_->ScrollBy(fling_parameters_.point,
-                                            clipped_increment);
-      break;
-  }
-
-  if (did_scroll) {
-    fling_parameters_.cumulativeScroll.width += clipped_increment.width;
-    fling_parameters_.cumulativeScroll.height += clipped_increment.height;
-  }
-}
-
-void InputHandlerProxy::notifyCurrentFlingVelocity(
-    const WebFloatSize& velocity) {
-  TRACE_EVENT2("renderer",
-               "InputHandlerProxy::notifyCurrentFlingVelocity",
-               "vx",
-               velocity.width,
-               "vy",
-               velocity.height);
-  input_handler_->NotifyCurrentFlingVelocity(ToClientScrollIncrement(velocity));
-}
-
 }  // namespace content