Move compositor thread input handling logic into content

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
new file mode 100644
index 0000000000000000000000000000000000000000..d04b7f7137c9d3af87ccb55d481e5baab8db914a
--- /dev/null
+++ b/content/renderer/gpu/input_handler_proxy.cc
@@ -0,0 +1,404 @@
+// 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/Source/Platform/chromium/public/Platform.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
+
+using WebKit::WebFloatPoint;
+using WebKit::WebFloatSize;
+using WebKit::WebGestureEvent;
+using WebKit::WebInputEvent;
+using WebKit::WebMouseWheelEvent;
+using WebKit::WebPoint;
+using WebKit::WebScrollbar;
+using WebKit::WebTouchEvent;
+
+namespace content {
+
+InputHandlerProxy::InputHandlerProxy(cc::InputHandler* input_handler)
+    : client_(NULL),
+      input_handler_(input_handler),
+#ifndef NDEBUG
+      expect_scroll_update_end_(false),
+      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) {
+  input_handler_->BindToClient(this);
+}
+
+InputHandlerProxy::~InputHandlerProxy() {}
+
+void InputHandlerProxy::WillShutdown() {
+  if (client_)

[piman, 2013/05/15 21:51:03]

maybe DCHECK(client_)? Since WillShutdown is what is meant to destroy |this|, I
don't think we can allow client_ to be NULL here.

+    client_->WillShutdown();
+}
+
+void InputHandlerProxy::SetClient(InputHandlerProxyClient* client) {
+  DCHECK(!client_);
+  client_ = client;
+}
+
+void InputHandlerProxy::HandleInputEvent(const WebInputEvent& event) {
+  DCHECK(client_);
+
+  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_->DidReceiveLastInputEventForVSync(
+        base::TimeTicks::FromInternalValue(event.timeStampSeconds *
+                                           base::Time::kMicrosecondsPerSecond));
+  }
+}
+
+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;
+    }
+    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;
+      }
+      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;
+      case cc::InputHandler::ScrollOnMainThread:
+        return DidNotHandle;
+    }
+  } 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;
+      case cc::InputHandler::ScrollOnMainThread:
+        return DidNotHandle;
+      case cc::InputHandler::ScrollIgnored:
+        return DropEvent;
+    }
+  } 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;
+
+    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;
+  } 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;
+
+    input_handler_->ScrollEnd();
+    gesture_scroll_on_impl_thread_ = false;
+    return DidHandle;
+  } 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;
+  } 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;
+  } 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;
+  } 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;
+    else if (!fling_may_be_active_on_main_thread_)
+      return DropEvent;
+  } 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;
+  } else if (WebInputEvent::isKeyboardEventType(event.type)) {
+    CancelCurrentFling();
+  }
+
+  return DidNotHandle;
+}
+
+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()));
+      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 DidHandle;
+    }
+    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;
+    }
+    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 DropEvent;
+    }
+  }
+  return DidNotHandle;
+}
+
+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;
+}
+
+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 =
+      HandleInputEventInternal(synthetic_wheel);
+  switch (disposition) {
+    case DidHandle:
+      return true;
+    case DropEvent:
+      break;
+    case DidNotHandle:
+      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.
+      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) {
+  if (increment == WebFloatSize())
+    return;
+
+  TRACE_EVENT2("renderer",
+               "InputHandlerProxy::scrollBy",
+               "x",
+               increment.width,
+               "y",
+               increment.height);
+
+  bool did_scroll = false;
+
+  switch (fling_parameters_.sourceDevice) {
+    case WebGestureEvent::Touchpad:
+      did_scroll = TouchpadFlingScroll(increment);
+      break;
+    case WebGestureEvent::Touchscreen:
+      did_scroll = input_handler_->ScrollBy(fling_parameters_.point,
+                                            ToClientScrollIncrement(increment));
+      break;
+  }
+
+  if (did_scroll) {
+    fling_parameters_.cumulativeScroll.width += increment.width;
+    fling_parameters_.cumulativeScroll.height += 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