ash: Add some UMA for touch-events.

ash/touch/touch_uma.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 "ash/touch/touch_uma.h"
 
+#include "ash/shell_delegate.h"
 #include "base/metrics/histogram.h"
 #include "base/stringprintf.h"
 #include "ui/aura/event.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 
 namespace {
 
 enum GestureActionType {
   GESTURE_UNKNOWN,
@@ skipping 200 matching lines @@
   GestureActionType action = FindGestureActionType(target, event);
   if (action != GESTURE_UNKNOWN) {
     UMA_HISTOGRAM_ENUMERATION("Ash.GestureTarget",
                               action,
                               GESTURE_ACTION_COUNT);
   }
 }
 
 void TouchUMA::RecordTouchEvent(aura::Window* target,
                                 const aura::TouchEvent& event) {
-  // TODO(sad|rjkroege): Figure out what to do (heat map?).
+  if (event.type() == ui::ET_TOUCH_PRESSED) {
+    Shell::GetInstance()->delegate()->RecordUserMetricsAction(
+        UMA_TOUCHSCREEN_TAP_DOWN);
+  }
+
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Ash.TouchRadius",
+      static_cast<int>(std::max(event.radius_x(), event.radius_y())),
+      1, 500, 100);

[Rick Byers, 2012/07/31 20:37:36]

This seems reasonable to me.  We've seen radii > 500 on some devices with buggy
firmware, but it looks like that'll just go into the overflow bucket.  

 }
 
 }  // namespace internal
 }  // namespace ash