Change ui::Event::time_stamp from TimeDelta to TimeTicks

ash/shelf/shelf_view.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 "ash/shelf/shelf_view.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "ash/ash_constants.h"
@@ skipping 1855 matching lines @@
       snap_back_from_rip_off_view_ = nullptr;
     }
   }
 }
 
 bool ShelfView::IsRepostEvent(const ui::Event& event) {
   if (closing_event_time_.is_zero())
     return false;
 
   base::TimeDelta delta =
-      base::TimeDelta(event.time_stamp() - closing_event_time_);
+      (event.time_stamp() - closing_event_time_) - base::TimeTicks();
   closing_event_time_ = base::TimeDelta();

[miu, 2016/05/16 20:05:35]

IIUC, closing_event_time_ needs to be changed to be of type base::TimeTicks.

[majidvp, 2016/05/21 01:38:00]

It should be eventually but I prefer to make that change in a
separate patch. 

This value get initialized from MenuRunner::closing_event_time.
I din't want to change that interface in this patch to contain the
scope. But I have a TODO in menu_controller.h about
the need for this change.

   // If the current (press down) event is a repost event, the time stamp of
   // these two events should be the same.
   return (delta.InMilliseconds() == 0);

[miu, 2016/05/16 20:05:35]

The comment suggests this is a bug. Shouldn't this code be:

  base::TimeTicks last_closing_event_time = closing_event_time_;
  closing_event_time_ = base::TimeTicks();
  // <comment>
  return event.time_stamp() == last_closing_event_time;

[majidvp, 2016/05/21 01:38:00]

I don't see how this logic is different from the existing logic.
The result is the same.

[miu, 2016/05/25 01:42:31]

What if |delta| is 999 usec? Then |delta.InMilliseconds() == 0| will be true
(integer truncation after usec are divided by 1000), but clearly there were two
distinct timestamps almost a full millisecond apart; and this indicates the
event is not a "repost event" as the comment states.

[majidvp, 2016/05/27 14:34:15]

Doh! I totally missed the milliseconds conversion. Fixed.

 }
 
 const ShelfItem* ShelfView::ShelfItemForView(const views::View* view) const {
   const int view_index = view_model_->GetIndexOfView(view);
   return (view_index < 0) ? nullptr : &(model_->items()[view_index]);
 }
 
 int ShelfView::CalculateShelfDistance(const gfx::Point& coordinate) const {
   const gfx::Rect bounds = GetBoundsInScreen();
   int distance = shelf_->SelectValueForShelfAlignment(
       bounds.y() - coordinate.y(), coordinate.x() - bounds.right(),
       bounds.x() - coordinate.x());
   return distance > 0 ? distance : 0;
 }
 
 }  // namespace ash