Touch emulator: allow multiple touch streams.

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 2012 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/render_widget_host_impl.h"
 
 #include <math.h>
 #include <set>
 #include <utility>
 
@@ skipping 946 matching lines @@
           original_component.sequence_number,
           original_component.event_time,
           original_component.event_count);
     }
   }
 
   GestureEventWithLatencyInfo gesture_with_latency(gesture_event, latency_info);
   input_router_->SendGestureEvent(gesture_with_latency);
 }
 
-void RenderWidgetHostImpl::ForwardTouchEvent(
+void RenderWidgetHostImpl::ForwardEmulatedTouchEvent(
       const blink::WebTouchEvent& touch_event) {
-  ForwardTouchEventWithLatencyInfo(touch_event, ui::LatencyInfo());
+  TRACE_EVENT0("input", "RenderWidgetHostImpl::ForwardEmulatedTouchEvent");
+  ui::LatencyInfo latency_info =
+      CreateRWHLatencyInfoIfNotExist(NULL, touch_event.type);
+  TouchEventWithLatencyInfo touch_with_latency(touch_event, latency_info);
+  input_router_->SendTouchEvent(touch_with_latency);
 }
 
 void RenderWidgetHostImpl::ForwardTouchEventWithLatencyInfo(
       const blink::WebTouchEvent& touch_event,
       const ui::LatencyInfo& ui_latency) {
   TRACE_EVENT0("input", "RenderWidgetHostImpl::ForwardTouchEvent");
 
   // Always forward TouchEvents for touch stream consistency. They will be
   // ignored if appropriate in FilterInputEvent().
 
   ui::LatencyInfo latency_info =
       CreateRWHLatencyInfoIfNotExist(&ui_latency, touch_event.type);
   TouchEventWithLatencyInfo touch_with_latency(touch_event, latency_info);
+
+  if (touch_emulator_ &&
+      touch_emulator_->HandleTouchEvent(touch_with_latency.event)) {
+    if (view_) {
+      view_->ProcessAckedTouchEvent(
+          touch_with_latency, INPUT_EVENT_ACK_STATE_CONSUMED);
+    }
+    return;
+  }
+
   input_router_->SendTouchEvent(touch_with_latency);
 }
 
 void RenderWidgetHostImpl::ForwardKeyboardEvent(
     const NativeWebKeyboardEvent& key_event) {
   TRACE_EVENT0("input", "RenderWidgetHostImpl::ForwardKeyboardEvent");
   if (IgnoreInputEvents())
     return;
 
   if (!process_->HasConnection())
@@ skipping 896 matching lines @@
   touch_event.latency.AddLatencyNumber(
       ui::INPUT_EVENT_LATENCY_ACKED_TOUCH_COMPONENT, 0, 0);
   // TouchEvent latency ends at ack if it didn't cause any rendering.
   if (!touch_event.latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_COMPONENT, 0, NULL)) {
     touch_event.latency.AddLatencyNumber(
         ui::INPUT_EVENT_LATENCY_TERMINATED_TOUCH_COMPONENT, 0, 0);
   }
   ComputeTouchLatency(touch_event.latency);
 
-  if (touch_emulator_ && touch_emulator_->HandleTouchEventAck(ack_result))
+  if (touch_emulator_ &&
+      touch_emulator_->HandleTouchEventAck(event.event, ack_result)) {
     return;
+  }
 
   if (view_)
     view_->ProcessAckedTouchEvent(touch_event, ack_result);
 }
 
 void RenderWidgetHostImpl::OnUnexpectedEventAck(UnexpectedEventAckType type) {
   if (type == BAD_ACK_MESSAGE) {
     RecordAction(base::UserMetricsAction("BadMessageTerminate_RWH2"));
     process_->ReceivedBadMessage();
   } else if (type == UNEXPECTED_EVENT_TYPE) {
     suppress_next_char_events_ = false;
   }
 }
 
 void RenderWidgetHostImpl::OnSyntheticGestureCompleted(
     SyntheticGesture::Result result) {
   Send(new InputMsg_SyntheticGestureCompleted(GetRoutingID()));
 }
 
 const gfx::Vector2d& RenderWidgetHostImpl::GetLastScrollOffset() const {
   return last_scroll_offset_;
 }
 
 bool RenderWidgetHostImpl::IgnoreInputEvents() const {
   return ignore_input_events_ || process_->IgnoreInputEvents();
 }
 
 bool RenderWidgetHostImpl::ShouldForwardTouchEvent() const {
   return input_router_->ShouldForwardTouchEvent();

[jdduke (slow), 2014/07/16 15:17:03]

So, one intermediate solution (kind of hacky) would be to change this to:

// It's important that the emulator sees a complete native touch stream,
allowing it to perform touch filtering as appropriate.
// TODO(jdduke): Remove when touch stream forwarding issues resolved, see
crbug.com/375940.
if (touch_emulator_ && touch_emulator_->enabled())
  return true;

return input_router_->ShouldForwardTouchEvent();

 }
 
 void RenderWidgetHostImpl::StartUserGesture() {
   OnUserGesture();
 }
 
 void RenderWidgetHostImpl::Stop() {
   Send(new ViewMsg_Stop(GetRoutingID()));
 }
 
@@ skipping 441 matching lines @@
   }
 }
 
 SkColorType RenderWidgetHostImpl::PreferredReadbackFormat() {
   if (view_)
     return view_->PreferredReadbackFormat();
   return kN32_SkColorType;
 }
 
 }  // namespace content