Add Vector2d classes that represent offsets, instead of using Point.

ui/base/gestures/gesture_recognizer_impl.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_recognizer_impl.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "ui/base/events/event.h"
@@ skipping 114 matching lines @@
 GestureConsumer* GestureRecognizerImpl::GetTargetForLocation(
     const gfx::Point& location) {
   const GesturePoint* closest_point = NULL;
   int closest_distance_squared = 0;
   std::map<GestureConsumer*, GestureSequence*>::iterator i;
   for (i = consumer_sequence_.begin(); i != consumer_sequence_.end(); ++i) {
     const GesturePoint* points = i->second->points();
     for (int j = 0; j < GestureSequence::kMaxGesturePoints; ++j) {
       if (!points[j].in_use())
         continue;
-      gfx::Point delta =
-          points[j].last_touch_position().Subtract(location);
+      gfx::Vector2d delta = points[j].last_touch_position() - location;
       int distance = delta.x() * delta.x() + delta.y() * delta.y();

[Peter Kasting, 2012/10/30 01:14:14]

Nit: Use LengthSquared() and add comments/change names as you did earlier in
this CL.

       if (!closest_point || distance < closest_distance_squared) {
         closest_point = &points[j];
         closest_distance_squared = distance;
       }
     }
   }
 
   const int max_distance =
       GestureConfiguration::max_separation_for_gesture_touches_in_pixels();
 
@@ skipping 90 matching lines @@
   RemoveConsumerFromMap(consumer, &touch_id_target_);
   RemoveConsumerFromMap(consumer, &touch_id_target_for_gestures_);
 }
 
 // GestureRecognizer, static
 GestureRecognizer* GestureRecognizer::Create(GestureEventHelper* helper) {
   return new GestureRecognizerImpl(helper);
 }
 
 }  // namespace ui