touch: Make sure the correct radius values are used for touch events.

ui/aura/event.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/aura/event.h"
 
 #if defined(USE_X11)
 #include <X11/Xlib.h>
 #endif
 
@@ skipping 253 matching lines @@
       rotation_angle_(model.rotation_angle_),
       force_(model.force_) {
 }
 
 TouchEvent::TouchEvent(ui::EventType type,
                        const gfx::Point& location,
                        int touch_id,
                        base::TimeDelta time_stamp)
     : LocatedEvent(type, location, location, 0),
       touch_id_(touch_id),
-      radius_x_(1.0f),
-      radius_y_(1.0f),
+      radius_x_(0.0f),
+      radius_y_(0.0f),
       rotation_angle_(0.0f),
       force_(0.0f) {
   set_time_stamp(time_stamp);
 }
 
 TouchEvent::~TouchEvent() {
 }
 
 void TouchEvent::UpdateForRootTransform(const ui::Transform& root_transform) {
   LocatedEvent::UpdateForRootTransform(root_transform);
   gfx::Point3f scale;
   ui::InterpolatedTransform::FactorTRS(root_transform, NULL, NULL, &scale);
-  radius_x_ *= scale.x();
-  radius_y_ *= scale.y();
+  if (scale.x())
+    radius_x_ /= scale.x();
+  if (scale.y())
+    radius_y_ /= scale.y();
 }
 
 ui::EventType TouchEvent::GetEventType() const {
   return type();
 }
 
 gfx::Point TouchEvent::GetLocation() const {
   return location();
 }
 
@@ skipping 179 matching lines @@
 int GestureEvent::GetLowestTouchId() const {
   if (touch_ids_bitfield_ == 0)
     return -1;
   int i = -1;
   // Find the index of the least significant 1 bit
   while (!(1 << ++i & touch_ids_bitfield_));
   return i;
 }
 
 }  // namespace aura