Calibrating touch input

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index aeb3651bd788d7937dfccff504cd475a57a3de6f..3bad2d0f11c24212bf24420e146a484f56e62d21 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -310,7 +310,8 @@ bool RootWindow::DispatchTouchEvent(TouchEvent* event) {
       // If the touch is outside the root window, set its target to the
       // root window.
       target = this;
-    } else {
+    } else if (target != this) {
+      // We only come here when the first contact was within the root window.

[sadrul, 2012/05/04 14:02:56]

I don't think this is necessary. But if we want to ensure our assumption that
'target != this' is always correct, then let's add a DCHECK_NE(this, target)
here instead.

[Mr4D (OOO till 08-26), 2012/05/04 15:01:06]

Actually... It *is* needed. The "touch down" works well, but each consecutive
call will then enter this loop and crash a little bit further down because the
target seems to cause trouble. If I remember it right the ProcessTouchEvent was
the function crashing. If that part is needed for the processing I will have to
dig further down where exactly it crashes (but without debugger that is.. oh
well).

       if (!target)
         target = GetEventHandlerForPoint(event->location());
       if (!target)