Calibrating touch input

ui/aura/root_window.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/root_window.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 292 matching lines @@
 
     if (!target) {
       target = static_cast<Window*>(
           gesture_recognizer_->GetTargetForLocation(event->GetLocation()));
     }
 
     if (!target && !bounds().Contains(event->location())) {
       // 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)
         return false;
 
       TouchEvent translated_event(*event, this, target);
       status = ProcessTouchEvent(target, &translated_event);
       handled = status != ui::TOUCH_STATUS_UNKNOWN;
 
       if (status == ui::TOUCH_STATUS_QUEUED ||
@@ skipping 662 matching lines @@
 void RootWindow::UnlockCompositor() {
   DCHECK(compositor_lock_);
   compositor_lock_ = NULL;
   if (draw_on_compositor_unlock_) {
     draw_on_compositor_unlock_ = false;
     ScheduleDraw();
   }
 }
 
 }  // namespace aura