Remove KeyboardUmaEventFilter

ash/keyboard_uma_event_filter.cc

-// Copyright 2013 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/keyboard_uma_event_filter.h"
-
-#include "base/metrics/histogram.h"
-#include "ui/events/event.h"
-
-namespace {
-
-// This threshold is used to drop keystrokes that are more than some time apart.
-// These keystrokes are dropped to avoid recording outliers, as well as pauses
-// between actual segments of typing.
-const int kKeystrokeThresholdInSeconds = 5;
-}
-
-namespace ash {
-
-KeyboardUMAEventFilter::KeyboardUMAEventFilter() {}
-
-KeyboardUMAEventFilter::~KeyboardUMAEventFilter() {}
-
-void KeyboardUMAEventFilter::OnKeyEvent(ui::KeyEvent* event) {
-  // This is a rough approximation, so assume that each key release is the
-  // result of a typed key.
-  if (event->type() != ui::ET_KEY_RELEASED)
-    return;
-
-  // Reset the timer on non-character keystrokes.
-  if (!isprint(event->GetCharacter())) {
-    last_keystroke_time_ = base::TimeTicks();
-    return;
-  }
-
-  if (last_keystroke_time_.ToInternalValue() == 0) {
-    last_keystroke_time_ = event->time_stamp();
-    return;
-  }
-
-  base::TimeDelta delta = event->time_stamp() - last_keystroke_time_;
-  if (delta < base::TimeDelta::FromSeconds(kKeystrokeThresholdInSeconds))
-    UMA_HISTOGRAM_TIMES("Keyboard.KeystrokeDeltas", delta);
-
-  last_keystroke_time_ = event->time_stamp();
-}
-
-}  // namespace ash