Plugin Power Saver: Refactor Plugin Instance Throttling code

content/renderer/pepper/pepper_plugin_instance_throttler.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/pepper_plugin_instance_throttler.h"
 
+#include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/time/time.h"
+#include "content/public/common/content_constants.h"
+#include "content/public/common/content_switches.h"
+#include "content/renderer/pepper/plugin_power_saver_helper.h"
+#include "content/renderer/render_thread_impl.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 
 namespace content {
 
 namespace {
 
+static const int kInfiniteRatio = 99999;
+
+#define UMA_HISTOGRAM_ASPECT_RATIO(name, width, height) \
+  UMA_HISTOGRAM_SPARSE_SLOWLY(                          \
+      name, (height) ? ((width)*100) / (height) : kInfiniteRatio);
+
+// Histogram tracking prevalence of tiny Flash instances. Units in pixels.
+enum PluginFlashTinyContentSize {
+  TINY_CONTENT_SIZE_1_1 = 0,
+  TINY_CONTENT_SIZE_5_5 = 1,
+  TINY_CONTENT_SIZE_10_10 = 2,
+  TINY_CONTENT_SIZE_LARGE = 3,
+  TINY_CONTENT_SIZE_NUM_ITEMS
+};
+
+// How the throttled power saver is unthrottled, if ever.
+// These numeric values are used in UMA logs; do not change them.
+enum PowerSaverUnthrottleMethod {
+  UNTHROTTLE_METHOD_NEVER = 0,
+  UNTHROTTLE_METHOD_BY_CLICK = 1,
+  UNTHROTTLE_METHOD_BY_WHITELIST = 2,
+  UNTHROTTLE_METHOD_NUM_ITEMS
+};
+
+const char kFlashClickSizeAspectRatioHistogram[] =
+    "Plugin.Flash.ClickSize.AspectRatio";
+const char kFlashClickSizeHeightHistogram[] = "Plugin.Flash.ClickSize.Height";
+const char kFlashClickSizeWidthHistogram[] = "Plugin.Flash.ClickSize.Width";
+const char kFlashTinyContentSizeHistogram[] = "Plugin.Flash.TinyContentSize";
+const char kPowerSaverUnthrottleHistogram[] = "Plugin.PowerSaver.Unthrottle";
+
+// Record size metrics for all Flash instances.
+void RecordFlashSizeMetric(int width, int height) {
+  PluginFlashTinyContentSize size = TINY_CONTENT_SIZE_LARGE;
+
+  if (width <= 1 && height <= 1)
+    size = TINY_CONTENT_SIZE_1_1;
+  else if (width <= 5 && height <= 5)
+    size = TINY_CONTENT_SIZE_5_5;
+  else if (width <= 10 && height <= 10)
+    size = TINY_CONTENT_SIZE_10_10;
+
+  UMA_HISTOGRAM_ENUMERATION(kFlashTinyContentSizeHistogram, size,
+                            TINY_CONTENT_SIZE_NUM_ITEMS);
+}
+
+void RecordUnthrottleMethodMetric(PowerSaverUnthrottleMethod method) {
+  UMA_HISTOGRAM_ENUMERATION(kPowerSaverUnthrottleHistogram, method,
+                            UNTHROTTLE_METHOD_NUM_ITEMS);
+}
+
+// Records size metrics for Flash instances that are clicked.
+void RecordFlashClickSizeMetric(int width, int height) {
+  base::HistogramBase* width_histogram = base::LinearHistogram::FactoryGet(
+      kFlashClickSizeWidthHistogram,
+      0,    // minimum width
+      500,  // maximum width
+      100,  // number of buckets.
+      base::HistogramBase::kUmaTargetedHistogramFlag);
+  width_histogram->Add(width);
+
+  base::HistogramBase* height_histogram = base::LinearHistogram::FactoryGet(
+      kFlashClickSizeHeightHistogram,
+      0,    // minimum height
+      400,  // maximum height
+      100,  // number of buckets.
+      base::HistogramBase::kUmaTargetedHistogramFlag);
+  height_histogram->Add(height);
+
+  UMA_HISTOGRAM_ASPECT_RATIO(kFlashClickSizeAspectRatioHistogram, width,
+                             height);
+}
+
 // 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;
-}
+
+}  // namespace
 
 PepperPluginInstanceThrottler::PepperPluginInstanceThrottler(
-    const base::Closure& throttle_closure) {
-  DCHECK(!throttle_closure.is_null());
-  base::MessageLoop::current()->PostDelayedTask(
-      FROM_HERE, throttle_closure,
-      base::TimeDelta::FromMilliseconds(kThrottleTimeout));
+    PluginPowerSaverHelper* power_saver_helper,
+    const blink::WebRect& bounds,
+    const std::string& module_name,
+    const GURL& plugin_url,
+    const base::Closure& throttle_change_callback)
+    : bounds_(bounds),
+      throttle_change_callback_(throttle_change_callback),
+      is_flash_plugin_(module_name == kFlashPluginName),
+      has_been_clicked_(false),
+      power_saver_enabled_(false),
+      is_peripheral_content_(false),
+      plugin_throttled_(false),
+      weak_factory_(this) {
+  GURL content_origin = plugin_url.GetOrigin();
+
+  if (is_flash_plugin_ && RenderThread::Get()) {
+    RenderThread::Get()->RecordAction(
+        base::UserMetricsAction("Flash.PluginInstanceCreated"));
+    RecordFlashSizeMetric(bounds.width, bounds.height);
+  }
+
+  bool cross_origin = false;
+  is_peripheral_content_ =
+      is_flash_plugin_ &&
+      power_saver_helper->ShouldThrottleContent(content_origin, bounds.width,
+                                                bounds.height, &cross_origin);
+
+  power_saver_enabled_ = is_peripheral_content_ &&
+                         base::CommandLine::ForCurrentProcess()->HasSwitch(
+                             switches::kEnablePluginPowerSaver);
+
+  if (is_peripheral_content_) {
+    // To collect UMAs, register peripheral content even if we don't throttle.
+    power_saver_helper->RegisterPeripheralPlugin(
+        content_origin, base::Bind(&PepperPluginInstanceThrottler::
+                                       DisablePowerSaverByRetroactiveWhitelist,
+                                   weak_factory_.GetWeakPtr()));
+
+    if (power_saver_enabled_) {
+      base::MessageLoop::current()->PostDelayedTask(
+          FROM_HERE,
+          base::Bind(&PepperPluginInstanceThrottler::SetPluginThrottled,
+                     weak_factory_.GetWeakPtr(), true /* throttled */),
+          base::TimeDelta::FromMilliseconds(kThrottleTimeout));
+    }
+  } else if (cross_origin) {
+    power_saver_helper->WhitelistContentOrigin(content_origin);
+  }
 }
 
 PepperPluginInstanceThrottler::~PepperPluginInstanceThrottler() {
 }
 
+bool PepperPluginInstanceThrottler::ConsumeInputEvent(
+    const blink::WebInputEvent& event) {
+  if (!has_been_clicked_ && is_flash_plugin_ &&
+      event.type == blink::WebInputEvent::MouseDown) {
+    has_been_clicked_ = true;
+    RecordFlashClickSizeMetric(bounds_.width, bounds_.height);
+  }
+
+  if (event.type == blink::WebInputEvent::MouseUp && is_peripheral_content_) {
+    is_peripheral_content_ = false;
+    power_saver_enabled_ = false;
+
+    RecordUnthrottleMethodMetric(UNTHROTTLE_METHOD_BY_CLICK);
+
+    if (plugin_throttled_) {
+      SetPluginThrottled(false /* throttled */);
+      return true;
+    }
+  }
+
+  return plugin_throttled_;
+}
+
+void PepperPluginInstanceThrottler::SetPluginThrottled(bool throttled) {
+  // Do not throttle if we've already disabled power saver.
+  if (!power_saver_enabled_ && throttled)
+    return;
+
+  plugin_throttled_ = throttled;
+  throttle_change_callback_.Run();
+}
+
+void PepperPluginInstanceThrottler::DisablePowerSaverByRetroactiveWhitelist() {
+  if (!is_peripheral_content_)
+    return;
+
+  is_peripheral_content_ = false;
+  power_saver_enabled_ = false;
+  SetPluginThrottled(false);
+
+  RecordUnthrottleMethodMetric(UNTHROTTLE_METHOD_BY_WHITELIST);
+}
+
 }  // namespace content