ui: Remove gfx::Size::ClampToNonNegative, prevent negative sizes always.

ui/base/gestures/gesture_sequence.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 "ui/base/gestures/gesture_sequence.h"
 
 #include <cmath>
 #include <stdlib.h>
 
 #include "base/basictypes.h"
@@ skipping 567 matching lines @@
     }
   }
   return gestures.release();
 }
 
 void GestureSequence::RecreateBoundingBox() {
   // TODO(sad): Recreating the bounding box at every touch-event is not very
   // efficient. This should be made better.
   if (point_count_ == 1) {
     bounding_box_ = GetPointByPointId(0)->enclosing_rectangle();
   } else {

[sadrul, 2012/11/12 01:28:02]

You can set bounding_box_ to empty when point_count_ == 0 (so you don't need to
use empty_box below)

[danakj, 2012/11/12 05:45:56]

Done.

     int left = INT_MAX / 20, top = INT_MAX / 20;
     int right = INT_MIN / 20, bottom = INT_MIN / 20;
+    bool empty_box = true;
     for (int i = 0; i < kMaxGesturePoints; ++i) {
       if (!points_[i].in_use())
         continue;
       // Using the |enclosing_rectangle()| for the touch-points would be ideal.
       // However, this becomes brittle especially when a finger is in motion
       // because the change in radius can overshadow the actual change in
       // position. So the actual position of the point is used instead.
       const gfx::Point& point = points_[i].last_touch_position();
       left = std::min(left, point.x());
       right = std::max(right, point.x());
       top = std::min(top, point.y());
       bottom = std::max(bottom, point.y());
+      empty_box = false;
     }
-    bounding_box_.SetRect(left, top, right - left, bottom - top);
+    if (empty_box)
+      bounding_box_.SetRect(0, 0, 0, 0);
+    else
+      bounding_box_.SetRect(left, top, right - left, bottom - top);
   }
 }
 
 void GestureSequence::ResetVelocities() {
   for (int i = 0; i < kMaxGesturePoints; ++i) {
     if (points_[i].in_use())
       points_[i].ResetVelocity();
   }
 }
 
@@ skipping 556 matching lines @@
     return;
 
   // Since long press timer has been started, there should be a non-NULL point.
   const GesturePoint* point = GetPointByPointId(0);
   if (!ui::gestures::IsInsideManhattanSquare(point->first_touch_position(),
       event.location()))
     GetLongPressTimer()->Stop();
 }
 
 }  // namespace ui