Revert "Count number of active touches in TouchActionFilter"

This reverts commit 0ee23351.

Reason for revert: Top crash in canary and blocks dev release
per bug 880021.

Original change's description:
> Count number of active touches in TouchActionFilter
> 
> Right now we have a active_touch_in_progress_ to indicate whether there
> is an active touch or not. It is true when we receive ACK for touch
> start and false at touch end.
> 
> From the current crash report, we are seeing multiple consecutive ack
> for touch end, without any ack for touch start in between.
> 
> This CL changes the active_touch_in_progress_ to num_of_active_touches_.
> It is increased by one when we receive ack for touch start and decrease
> by one at touch end. At touch end, we only reset touch action when this
> number is zero.
> 
> In theory, touch start and associated touch end should arrive in pair.
> This CL does a DumpWithoutCrashing if this number is ever larger than
> one.
> 
> Bug: 851644
> Change-Id: I584f1aad56bf5bc5c08e20e3ae4ca36d5f9e3586
> Reviewed-on: https://chromium-review.googlesource.com/1196696
> Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
> Commit-Queue: Xida Chen <xidachen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#587813}

TBR=dtapuska@chromium.org,xidachen@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 851644, 880021
Change-Id: I265b573cef100ff6210683e7f5ec01dfcb28ea9f
Reviewed-on: https://chromium-review.googlesource.com/1205923Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588791}

content/browser/renderer_host/input/input_router_impl.cc

@@ -340,16 +340,16 @@ void InputRouterImpl::OnTouchEventAck(const TouchEventWithLatencyInfo& event,
   if (WebTouchEventTraits::IsTouchSequenceStart(event.event) &&
       ack_result == INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS) {
     touch_action_filter_.AppendToGestureSequenceForDebugging("T");
-    touch_action_filter_.IncreaseActiveTouches();
     // Touch action must be auto when there is no consumer
     touch_action_filter_.OnSetTouchAction(cc::kTouchActionAuto);
+    touch_action_filter_.SetActiveTouchInProgress(true);
     UpdateTouchAckTimeoutEnabled();
   }
   disposition_handler_->OnTouchEventAck(event, ack_source, ack_result);
 
   if (WebTouchEventTraits::IsTouchSequenceEnd(event.event)) {
-    touch_action_filter_.DecreaseActiveTouches();
     touch_action_filter_.ReportAndResetTouchAction();
+    touch_action_filter_.SetActiveTouchInProgress(false);
     UpdateTouchAckTimeoutEnabled();
   }
 }
@@ -530,11 +530,8 @@ void InputRouterImpl::TouchEventHandled(
   // The SetTouchAction IPC occurs on a different channel so always
   // send it in the input event ack to ensure it is available at the
   // time the ACK is handled.
-  if (touch_action.has_value()) {
-    if (WebTouchEventTraits::IsTouchSequenceStart(touch_event.event))
-      touch_action_filter_.IncreaseActiveTouches();
+  if (touch_action.has_value())
     OnSetTouchAction(touch_action.value());
-  }
 
   // |touch_event_queue_| will forward to OnTouchEventAck when appropriate.
   touch_event_queue_.ProcessTouchAck(source, state, latency,
@@ -599,6 +596,7 @@ void InputRouterImpl::OnHasTouchEventHandlers(bool has_handlers) {
 void InputRouterImpl::ForceSetTouchActionAuto() {
   touch_action_filter_.AppendToGestureSequenceForDebugging("F");
   touch_action_filter_.OnSetTouchAction(cc::kTouchActionAuto);
+  touch_action_filter_.SetActiveTouchInProgress(true);
 }
 
 void InputRouterImpl::OnHasTouchEventHandlersForTest(bool has_handlers) {
@@ -618,6 +616,7 @@ void InputRouterImpl::OnSetTouchAction(cc::TouchAction touch_action) {
   touch_action_filter_.AppendToGestureSequenceForDebugging(
       std::to_string(touch_action).c_str());
   touch_action_filter_.OnSetTouchAction(touch_action);
+  touch_action_filter_.SetActiveTouchInProgress(true);
 
   // kTouchActionNone should disable the touch ack timeout.
   UpdateTouchAckTimeoutEnabled();

content/browser/renderer_host/input/touch_action_filter.cc

@@ -7,7 +7,6 @@
 #include <math.h>
 
 #include "base/debug/crash_logging.h"
-#include "base/debug/dump_without_crashing.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "third_party/blink/public/platform/web_gesture_event.h"
@@ -241,19 +240,9 @@ void TouchActionFilter::OnSetTouchAction(cc::TouchAction touch_action) {
   scrolling_touch_action_ = allowed_touch_action_;
 }
 
-void TouchActionFilter::IncreaseActiveTouches() {
-  // The touch start and associated touch end should be acked in order. If not,
-  // dump.
-  if (num_of_active_touches_ > 0)
-    base::debug::DumpWithoutCrashing();
-  num_of_active_touches_++;
-}
-
-void TouchActionFilter::DecreaseActiveTouches() {
-  // Something is seriously wrong if this is true.
-  if (num_of_active_touches_ == 0)
-    base::debug::DumpWithoutCrashing();
-  num_of_active_touches_--;
+void TouchActionFilter::SetActiveTouchInProgress(
+    bool active_touch_in_progress) {
+  active_touch_in_progress_ = active_touch_in_progress;
 }
 
 void TouchActionFilter::ReportAndResetTouchAction() {
@@ -262,8 +251,7 @@ void TouchActionFilter::ReportAndResetTouchAction() {
   else
     gesture_sequence_.append("R0");
   ReportTouchAction();
-  if (num_of_active_touches_ <= 0)
-    ResetTouchAction();
+  ResetTouchAction();
 }
 
 void TouchActionFilter::ReportTouchAction() {
@@ -372,7 +360,7 @@ void TouchActionFilter::OnHasTouchEventHandlers(bool has_handlers) {
   // We have set the associated touch action if the touch start already happened
   // or there is a gesture in progress. In these cases, we should not reset the
   // associated touch action.
-  if (!gesture_sequence_in_progress_ && num_of_active_touches_ <= 0) {
+  if (!gesture_sequence_in_progress_ && !active_touch_in_progress_) {
     ResetTouchAction();
     if (has_touch_event_handler_)
       scrolling_touch_action_.reset();

content/browser/renderer_host/input/touch_action_filter.h

@@ -67,8 +67,7 @@ class CONTENT_EXPORT TouchActionFilter {
 
   void OnHasTouchEventHandlers(bool has_handlers);
 
-  void IncreaseActiveTouches();
-  void DecreaseActiveTouches();
+  void SetActiveTouchInProgress(bool active_touch_in_progress);
 
   // Debugging only.
   void AppendToGestureSequenceForDebugging(const char* str);
@@ -108,8 +107,8 @@ class CONTENT_EXPORT TouchActionFilter {
   // before GSE.
   bool gesture_sequence_in_progress_ = false;
 
-  // Increment at receiving ACK for touch start and decrement at touch end.
-  int num_of_active_touches_ = 0;
+  // True at touch start and false at touch end.
+  bool active_touch_in_progress_ = false;
 
   // What touch actions are currently permitted.
   base::Optional<cc::TouchAction> allowed_touch_action_;

content/browser/renderer_host/input/touch_action_filter_unittest.cc

@@ -1079,7 +1079,7 @@ TEST_F(TouchActionFilterTest, OnHasTouchEventHandlersReceivedAfterTouchStart) {
 
   // Receive a touch start ack, set the touch action.
   filter_.OnSetTouchAction(cc::kTouchActionPanY);
-  filter_.IncreaseActiveTouches();
+  filter_.SetActiveTouchInProgress(true);
   filter_.OnHasTouchEventHandlers(false);
   EXPECT_EQ(ScrollingTouchAction().value(), cc::kTouchActionPanY);
   EXPECT_EQ(filter_.allowed_touch_action().value(), cc::kTouchActionPanY);
@@ -1088,33 +1088,6 @@ TEST_F(TouchActionFilterTest, OnHasTouchEventHandlersReceivedAfterTouchStart) {
   EXPECT_EQ(filter_.allowed_touch_action().value(), cc::kTouchActionPanY);
 }
 
-TEST_F(TouchActionFilterTest, ResetTouchActionWithActiveTouch) {
-  filter_.OnHasTouchEventHandlers(true);
-  EXPECT_FALSE(ScrollingTouchAction().has_value());
-  EXPECT_FALSE(filter_.allowed_touch_action().has_value());
-
-  // Receive a touch start ack, set the touch action.
-  filter_.OnSetTouchAction(cc::kTouchActionPanY);
-  filter_.IncreaseActiveTouches();
-
-  // Somehow we get the ACK for the second touch start before the ACK for the
-  // first touch end.
-  filter_.OnSetTouchAction(cc::kTouchActionPan);
-  filter_.IncreaseActiveTouches();
-
-  // The first touch end comes, we report and reset touch action. The touch
-  // actions should still have value.
-  filter_.DecreaseActiveTouches();
-  filter_.ReportAndResetTouchAction();
-  EXPECT_EQ(ScrollingTouchAction().value(), cc::kTouchActionPanY);
-  EXPECT_EQ(filter_.allowed_touch_action().value(), cc::kTouchActionPanY);
-
-  // The ack for the second touch end comes, the touch actions will be reset.
-  filter_.DecreaseActiveTouches();
-  filter_.ReportAndResetTouchAction();
-  EXPECT_FALSE(filter_.allowed_touch_action().has_value());
-}
-
 // If the renderer is busy, the gesture event might have come before the
 // OnHasTouchEventHanlders IPC is received. In this case, we should allow all
 // the gestures.