Rename CancelAllTouches to the appropriate "MaybeCancelAllTouches".

By doing so, note that a break in a for loop is not appropriate when
not all items are cancelled. So only cancel if all items are
cancelled, etc.

Bug: 982118
Bug: 946868
Change-Id: I098eb046b9e0407493033b865ad6bb38a1ec5231
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1694281
Commit-Queue: Rob Schonberger <robsc@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676210}

ui/events/ozone/evdev/touch_event_converter_evdev.cc

@@ -250,7 +250,7 @@ void TouchEventConverterEvdev::Initialize(const EventDeviceInfo& info) {
     events_[0].cancelled = false;
   }
   if (cancelled_state)
-    CancelAllTouches();
+    MaybeCancelAllTouches();
 
   false_touch_finder_ = FalseTouchFinder::Create(GetTouchscreenSize());
 }
@@ -514,12 +514,12 @@ void TouchEventConverterEvdev::ReportTouchEvent(
       details, timestamp, flags));
 }
 
-void TouchEventConverterEvdev::CancelAllTouches() {
+bool TouchEventConverterEvdev::MaybeCancelAllTouches() {
   // TODO(denniskempin): Remove once upper layers properly handle single
   // cancelled touches.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableCancelAllTouches)) {
-    return;
+    return false;
   }
   for (size_t i = 0; i < events_.size(); i++) {
     InProgressTouchEvdev* event = &events_[i];
@@ -528,6 +528,7 @@ void TouchEventConverterEvdev::CancelAllTouches() {
       event->altered = true;
     }
   }
+  return true;
 }
 
 bool TouchEventConverterEvdev::IsPalm(const InProgressTouchEvdev& touch) {
@@ -552,10 +553,11 @@ void TouchEventConverterEvdev::ReportEvents(base::TimeTicks timestamp) {
     if (event->altered && (event->cancelled ||
                            (false_touch_finder_ &&
                             false_touch_finder_->SlotHasNoise(event->slot)))) {
-      CancelAllTouches();
+      if (MaybeCancelAllTouches()) {
         break;
       }
     }
+  }
 
   for (size_t i = 0; i < events_.size(); i++) {
     InProgressTouchEvdev* event = &events_[i];

ui/events/ozone/evdev/touch_event_converter_evdev.h

@@ -90,7 +90,8 @@ class EVENTS_OZONE_EVDEV_EXPORT TouchEventConverterEvdev
 
   void UpdateTrackingId(int slot, int tracking_id);
   void ReleaseTouches();
-  void CancelAllTouches();
+  // Returns true if all touches were marked cancelled. Otherwise false.
+  bool MaybeCancelAllTouches();
   bool IsPalm(const InProgressTouchEvdev& touch);
   // Normalize pressure value to [0, 1].
   float ScalePressure(int32_t value) const;