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 293 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 {
+      // We only come here when the first contact was within the root window.
       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 328 matching lines @@
     return false;
   return target->delegate()->OnKeyEvent(event);
 }
 
 ui::TouchStatus RootWindow::ProcessTouchEvent(Window* target,
                                               TouchEvent* event) {
   if (!target->IsVisible())
     return ui::TOUCH_STATUS_UNKNOWN;
 
   EventFilters filters;
-  GetEventFiltersToNotify(target->parent(), &filters);
+  if (target == this)
+    GetEventFiltersToNotify(target, &filters);
+  else
+    GetEventFiltersToNotify(target->parent(), &filters);
   for (EventFilters::const_reverse_iterator it = filters.rbegin(),
            rend = filters.rend();
        it != rend; ++it) {
     ui::TouchStatus status = (*it)->PreHandleTouchEvent(target, event);
     if (status != ui::TOUCH_STATUS_UNKNOWN)
       return status;
   }
 
-  return target->delegate()->OnTouchEvent(event);
+  if (target->delegate())
+    return target->delegate()->OnTouchEvent(event);
+
+  return ui::TOUCH_STATUS_UNKNOWN;
 }
 
 ui::GestureStatus RootWindow::ProcessGestureEvent(Window* target,
                                                   GestureEvent* event) {
   if (!target->IsVisible())
     return ui::GESTURE_STATUS_UNKNOWN;
 
   EventFilters filters;
   if (target == this)
     GetEventFiltersToNotify(target, &filters);
@@ skipping 304 matching lines @@
 void RootWindow::UnlockCompositor() {
   DCHECK(compositor_lock_);
   compositor_lock_ = NULL;
   if (draw_on_compositor_unlock_) {
     draw_on_compositor_unlock_ = false;
     ScheduleDraw();
   }
 }
 
 }  // namespace aura