Fix scaling for aura::GestureEvent and aura::TouchEvent

ui/aura/event.cc

Index: ui/aura/event.cc
diff --git a/ui/aura/event.cc b/ui/aura/event.cc
index 3fd6ab338f60d7f133b898236d4fa4224aeca497..637913491a987649cb946e06e4adc60c0315c9c6 100644
--- a/ui/aura/event.cc
+++ b/ui/aura/event.cc
@@ -13,6 +13,7 @@
 #include "ui/aura/window.h"
 #include "ui/base/keycodes/keyboard_code_conversion.h"
 #include "ui/gfx/point3.h"
+#include "ui/gfx/interpolated_transform.h"
 #include "ui/gfx/transform.h"
 
 #if defined(OS_MACOSX)
@@ -280,6 +281,14 @@ TouchEvent::TouchEvent(ui::EventType type,
 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();
+}
+
 ui::EventType TouchEvent::GetEventType() const {
   return type();
 }
@@ -454,6 +463,14 @@ GestureEvent::GestureEvent(const GestureEvent& model,
 GestureEvent::~GestureEvent() {
 }
 
+void GestureEvent::UpdateForRootTransform(const ui::Transform& root_transform) {
+  LocatedEvent::UpdateForRootTransform(root_transform);
+  gfx::Point3f scale;
+  ui::InterpolatedTransform::FactorTRS(root_transform, NULL, NULL, &scale);
+  delta_x_ *= scale.x();
+  delta_y_ *= scale.y();

[sadrul, 2012/04/22 19:35:55]

Are you sure the change here is necessary? The
pinch-scale/scroll-amount/velocity that these variables represent are usually
computed from the touch-event locations, and since the touch-event locations are
transformed properly, it is probably unnecessary to do this again here. (a test
might be useful)

[pkotwicz, 2012/04/23 00:15:40]

You are right that UpdateForRootTransform is never called on GestureEvent at
present. But this can change and it would be nice for this to be correct.

[sadrul, 2012/04/23 01:13:51]

I actually meant that the scale-factor on the root-window will already have been
taken into account by way of the touch-event location's transformation. So doing
this here again would mean the scale is applied twice, and that would be wrong.
So whether UpdateForRootTransform is applied or not, this change should not be
necessary.

+}
+
 int GestureEvent::GetLowestTouchId() const {
   if (touch_ids_bitfield_ == 0)
     return -1;