Clean up hack avoiding infinite loop in unit test.

ui/aura/gestures/gesture_recognizer_unittest.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 "base/command_line.h"
 #include "base/memory/scoped_vector.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/timer/timer.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 582 matching lines @@
  public:
   RemoveOnTouchCancelHandler() {}
   ~RemoveOnTouchCancelHandler() override {}
 
  private:
   // ui::EventHandler:
   void OnTouchEvent(ui::TouchEvent* event) override {
     TestEventHandler::OnTouchEvent(event);
     if (event->type() == ui::ET_TOUCH_CANCELLED) {
       Window* target = static_cast<Window*>(event->target());
-      // This is tiptoeing around crbug.com/310172. If this event handler isn't
-      // removed, we enter an infinite loop.
-      target->RemovePreTargetHandler(this);
       target->parent()->RemoveChild(target);
     }
   }
 
   DISALLOW_COPY_AND_ASSIGN(RemoveOnTouchCancelHandler);
 };
 
 void DelayByLongPressTimeout() {
   ui::GestureProvider::Config config;
   base::RunLoop run_loop;
@@ skipping 3739 matching lines @@
   // The synchronous ack is stuck behind the pending touch move.
   EXPECT_0_EVENTS(delegate->events());
 
   delegate->ReceivedAck();
   EXPECT_2_EVENTS(delegate->events(), ui::ET_GESTURE_SCROLL_UPDATE,
                   ui::ET_GESTURE_SCROLL_UPDATE);
 }
 
 }  // namespace test
 }  // namespace aura