Plugin Power Saver: Make Unthrottle metric collection more consistent

content/renderer/pepper/plugin_instance_throttler_impl.cc

 // Copyright 2014 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 "content/renderer/pepper/plugin_instance_throttler_impl.h"
 
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_thread.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/gfx/color_utils.h"
 #include "url/gurl.h"
 
 namespace content {
 
 namespace {
 
-const char kPowerSaverUnthrottleHistogram[] = "Plugin.PowerSaver.Unthrottle";
-
-void RecordUnthrottleMethodMetric(
-    PluginInstanceThrottlerImpl::PowerSaverUnthrottleMethod method) {
-  UMA_HISTOGRAM_ENUMERATION(
-      kPowerSaverUnthrottleHistogram, method,
-      PluginInstanceThrottler::UNTHROTTLE_METHOD_NUM_ITEMS);
-}
-
 // When we give up waiting for a suitable preview frame, and simply suspend
 // the plugin where it's at. In milliseconds.
 const int kThrottleTimeout = 5000;
 
 // Threshold for 'boring' score to accept a frame as good enough to be a
 // representative keyframe. Units are the ratio of all pixels that are within
 // the most common luma bin. The same threshold is used for history thumbnails.
 const double kAcceptableFrameMaximumBoringness = 0.94;
 
 const int kMinimumConsecutiveInterestingFrames = 4;
 
 }  // namespace
 
+// static
+scoped_ptr<PluginInstanceThrottler> PluginInstanceThrottler::Get(
+    RenderFrame* frame,
+    const GURL& plugin_url,
+    PluginPowerSaverMode power_saver_mode) {
+  if (power_saver_mode == PluginPowerSaverMode::POWER_SAVER_MODE_ESSENTIAL)
+    return nullptr;
+
+  bool power_saver_enabled =
+      power_saver_mode ==
+      PluginPowerSaverMode::POWER_SAVER_MODE_PERIPHERAL_THROTTLED;
+  return make_scoped_ptr(
+      new PluginInstanceThrottlerImpl(frame, plugin_url, power_saver_enabled));
+}
+
+// static
+void PluginInstanceThrottler::RecordUnthrottleMethodMetric(
+    PluginInstanceThrottlerImpl::PowerSaverUnthrottleMethod method) {
+  UMA_HISTOGRAM_ENUMERATION(
+      "Plugin.PowerSaver.Unthrottle", method,
+      PluginInstanceThrottler::UNTHROTTLE_METHOD_NUM_ITEMS);
+}
+
 PluginInstanceThrottlerImpl::PluginInstanceThrottlerImpl(
     RenderFrame* frame,
     const GURL& plugin_url,
     bool power_saver_enabled)
     : state_(power_saver_enabled ? POWER_SAVER_ENABLED_AWAITING_KEYFRAME
                                  : POWER_SAVER_DISABLED),
       consecutive_interesting_frames_(0),
       weak_factory_(this) {
   // To collect UMAs, register peripheral content even if power saver disabled.
   if (frame) {
     frame->RegisterPeripheralPlugin(
         plugin_url.GetOrigin(),
         base::Bind(&PluginInstanceThrottlerImpl::MarkPluginEssential,
                    weak_factory_.GetWeakPtr(), UNTHROTTLE_METHOD_BY_WHITELIST));
   }
 
   if (power_saver_enabled) {
     base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE, base::Bind(&PluginInstanceThrottlerImpl::EngageThrottle,
                               weak_factory_.GetWeakPtr()),
         base::TimeDelta::FromMilliseconds(kThrottleTimeout));
   }
 }
 
 PluginInstanceThrottlerImpl::~PluginInstanceThrottlerImpl() {
+  if (state_ != PLUGIN_INSTANCE_MARKED_ESSENTIAL)
+    RecordUnthrottleMethodMetric(UNTHROTTLE_METHOD_NEVER);
 }
 
 void PluginInstanceThrottlerImpl::AddObserver(Observer* observer) {
   observer_list_.AddObserver(observer);
 }
 
 void PluginInstanceThrottlerImpl::RemoveObserver(Observer* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
@@ skipping 51 matching lines @@
 
 void PluginInstanceThrottlerImpl::EngageThrottle() {
   if (state_ != POWER_SAVER_ENABLED_AWAITING_KEYFRAME)
     return;
 
   state_ = POWER_SAVER_ENABLED_PLUGIN_THROTTLED;
   FOR_EACH_OBSERVER(Observer, observer_list_, OnThrottleStateChange());
 }
 
 }  // namespace content