Revert of Move touch slop suppression from LegacyTouchEventQueue to TouchEventManager

content/browser/renderer_host/input/touch_event_queue.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/touch_event_queue.h"
 
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/macros.h"
@@ skipping 274 matching lines @@
   bool sequence_using_mobile_timeout_;
 };
 
 // Provides touchmove slop suppression for a touch sequence until a
 // (unprevented) touch will trigger immediate scrolling.
 class TouchEventQueue::TouchMoveSlopSuppressor {
  public:
   TouchMoveSlopSuppressor() : suppressing_touchmoves_(false) {}
 
   bool FilterEvent(const WebTouchEvent& event) {
-    suppressing_touchmoves_ = false;
-    return false;
+    if (WebTouchEventTraits::IsTouchSequenceStart(event)) {
+      suppressing_touchmoves_ = true;
+      touch_start_location_ = gfx::PointF(event.touches[0].position);
+    }
+
+    if (event.type() == WebInputEvent::TouchEnd ||
+        event.type() == WebInputEvent::TouchCancel)
+      suppressing_touchmoves_ = false;
+
+    if (event.type() != WebInputEvent::TouchMove)
+      return false;
+
+    if (suppressing_touchmoves_) {
+      if (event.touchesLength > 1) {
+        suppressing_touchmoves_ = false;
+      } else if (event.movedBeyondSlopRegion) {
+        suppressing_touchmoves_ = false;
+      } else {
+        // No sane slop region should be larger than 60 DIPs.
+        DCHECK_LT((gfx::PointF(event.touches[0].position) -
+                   touch_start_location_).LengthSquared(),
+                  kMaxConceivablePlatformSlopRegionLengthDipsSquared);
+      }
+    }
+
+    return suppressing_touchmoves_;
   }
 
   void ConfirmTouchEvent(InputEventAckState ack_result) {
     if (ack_result == INPUT_EVENT_ACK_STATE_CONSUMED)
       suppressing_touchmoves_ = false;
   }
 
   bool suppressing_touchmoves() const { return suppressing_touchmoves_; }
 
  private:
@@ skipping 605 matching lines @@
     if (ack_result == INPUT_EVENT_ACK_STATE_CONSUMED)
       send_touch_events_async_ = false;
     has_handler_for_current_sequence_ |=
         ack_result != INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
   } else if (WebTouchEventTraits::IsTouchSequenceEnd(event)) {
     has_handler_for_current_sequence_ = false;
   }
 }
 
 }  // namespace content