Coalesce async touch move events until the ack back from render

content/browser/renderer_host/input/input_router_impl.cc

 // Copyright 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/browser/renderer_host/input/input_router_impl.h"
 
 #include <math.h>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 230 matching lines @@
   current_view_flags_ = view_flags;
 
   // A fixed page scale or mobile viewport should disable the touch ack timeout.
   UpdateTouchAckTimeoutEnabled();
 }
 
 bool InputRouterImpl::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(InputRouterImpl, message)
     IPC_MESSAGE_HANDLER(InputHostMsg_HandleInputEvent_ACK, OnInputEventAck)
+    IPC_MESSAGE_HANDLER(InputHostMsg_HandleUncancelableTouchMoveEvent_ACK,
+                        OnUncancelableTouchMoveAck)
     IPC_MESSAGE_HANDLER(InputHostMsg_DidOverscroll, OnDidOverscroll)
     IPC_MESSAGE_HANDLER(InputHostMsg_MoveCaret_ACK, OnMsgMoveCaretAck)
     IPC_MESSAGE_HANDLER(InputHostMsg_SelectRange_ACK, OnSelectMessageAck)
     IPC_MESSAGE_HANDLER(InputHostMsg_MoveRangeSelectionExtent_ACK,
                         OnSelectMessageAck)
     IPC_MESSAGE_HANDLER(ViewHostMsg_HasTouchEventHandlers,
                         OnHasTouchEventHandlers)
     IPC_MESSAGE_HANDLER(InputHostMsg_SetTouchAction,
                         OnSetTouchAction)
     IPC_MESSAGE_UNHANDLED(handled = false)
@@ skipping 81 matching lines @@
   if (OfferToClient(input_event, latency_info))
     return;
 
   OfferToRenderer(input_event, latency_info, is_keyboard_shortcut);
 
   // Touch events should always indicate in the event whether they are
   // cancelable (respect ACK disposition) or not.
   bool ignores_ack = WebInputEventTraits::IgnoresAckDisposition(input_event);
   if (WebInputEvent::isTouchEventType(input_event.type)) {
     const WebTouchEvent& touch = static_cast<const WebTouchEvent&>(input_event);
-    DCHECK_NE(ignores_ack, !!touch.cancelable);
+    DCHECK_NE(ignores_ack, touch.cancelable);
   }
 
   // If we don't care about the ack disposition, send the ack immediately.
   if (ignores_ack) {
     ProcessInputEventAck(input_event.type,
                          INPUT_EVENT_ACK_STATE_IGNORED,
                          latency_info,
                          IGNORING_DISPOSITION);
   }
 }
@@ skipping 65 matching lines @@
   // (ProcessInputEventAck) method, but not on other platforms; using
   // 'void' instead is just as safe (since NotificationSource
   // is not actually typesafe) and avoids this error.
   int type = static_cast<int>(ack.type);
   NotificationService::current()->Notify(
       NOTIFICATION_RENDER_WIDGET_HOST_DID_RECEIVE_INPUT_EVENT_ACK,
       Source<void>(this),
       Details<int>(&type));
 }
 
+void InputRouterImpl::OnUncancelableTouchMoveAck() {
+  touch_event_queue_.ProcessUncancelableTouchMoveAck();
+}
+
 void InputRouterImpl::OnDidOverscroll(const DidOverscrollParams& params) {
   client_->DidOverscroll(params);
 }
 
 void InputRouterImpl::OnMsgMoveCaretAck() {
   move_caret_pending_ = false;
   if (next_move_caret_)
     SendMoveCaret(next_move_caret_.Pass());
 }
 
@@ skipping 182 matching lines @@
   return !touch_event_queue_.empty() ||
          !gesture_event_queue_.empty() ||
          !key_queue_.empty() ||
          mouse_move_pending_ ||
          mouse_wheel_pending_ ||
          select_message_pending_ ||
          move_caret_pending_;
 }
 
 }  // namespace content