touch: Filter touch events.

chrome/browser/renderer_host/render_widget_host_view_views.cc

 // Copyright (c) 2010 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 "chrome/browser/renderer_host/render_widget_host_view_views.h"
 
 #include <algorithm>
 #include <string>
 
 #include "app/l10n_util.h"
@@ skipping 699 matching lines @@
       break;
   }
 
   if (!point)
     return TOUCH_STATUS_UNKNOWN;
 
   if (status != TOUCH_STATUS_START)
     status = TOUCH_STATUS_CONTINUE;
 
   // Update the location and state of the point.
+  point->state = TouchPointStateFromEvent(&e);
+  if (point->state == WebKit::WebTouchPoint::StateMoved) {
+    // It is possible for badly written touch drivers to emit Move events even
+    // when the touch location hasn't changed. In such cases, consume the event
+    // and pretend nothing happened.
+    if (point->position.x == e.x() && point->position.y == e.y()) {
+      return status;
+    }
+  }
   UpdateTouchPointPosition(&e, GetPosition(), point);
-  point->state = TouchPointStateFromEvent(&e);
 
   // Mark the rest of the points as stationary.
   for (int i = 0; i < touch_event_.touchPointsLength; ++i) {
     WebKit::WebTouchPoint* iter = touch_event_.touchPoints + i;
     if (iter != point) {
       iter->state = WebKit::WebTouchPoint::StateStationary;
     }
   }
 
   // Update the type of the touch event.
@@ skipping 21 matching lines @@
 }
 
 // static
 RenderWidgetHostView*
     RenderWidgetHostView::GetRenderWidgetHostViewFromNativeView(
         gfx::NativeView widget) {
   gpointer user_data = g_object_get_data(G_OBJECT(widget),
                                          kRenderWidgetHostViewKey);
   return reinterpret_cast<RenderWidgetHostView*>(user_data);
 }