Fixed ui::TouchEvent rotation angle out-of-bound issue.

ui/events/event.cc

Index: ui/events/event.cc
diff --git a/ui/events/event.cc b/ui/events/event.cc
index 4c252d63639e476003615c17eeda5f79c6caed09..1877aaf69463df0c0370b5c284551510d63a4ebf 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -535,6 +535,7 @@ TouchEvent::TouchEvent(const base::NativeEvent& native_event)
       1);
 
   latency()->AddLatencyNumber(INPUT_EVENT_LATENCY_UI_COMPONENT, 0, 0);
+  fixRotationAngle();
 
   if (type() == ET_TOUCH_PRESSED)
     IncrementTouchIdRefCount(native_event);
@@ -573,6 +574,7 @@ TouchEvent::TouchEvent(EventType type,
       force_(force),
       may_cause_scrolling_(false) {
   latency()->AddLatencyNumber(INPUT_EVENT_LATENCY_UI_COMPONENT, 0, 0);
+  fixRotationAngle();
 }
 
 TouchEvent::~TouchEvent() {
@@ -601,6 +603,11 @@ void TouchEvent::DisableSynchronousHandling() {
       static_cast<EventResult>(result() | ER_DISABLE_SYNC_HANDLING));
 }
 
+void TouchEvent::fixRotationAngle() {

[tdresser, 2015/01/20 13:36:39]

The bounds are [-90, 90], correct? So this should be < and >, not <= and >=?

I don't think taking the number mod 90 is correct. Don't you need to swap the
major/minor (x/y) axis in this case as well?

[mustaq, 2015/01/20 16:26:46]

Good catch, thanks. I have adjusted the angle range:
- to an open interval to avoid having multiple sets of values representing a
single ellipse, and
- to a positive interval to fix the mod issue.

+  if (rotation_angle_ <= -90 || rotation_angle_ >= 90)
+      rotation_angle_ = fmod(rotation_angle_, 90);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // KeyEvent