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/time/time.h"
+#include "content/public/common/content_constants.h"
+#include "content/public/common/content_switches.h"
+#include "content/renderer/pepper/plugin_module.h"
+#include "content/renderer/pepper/pepper_plugin_instance_impl.h"
+#include "content/renderer/pepper/plugin_power_saver_helper.h"
+#include "content/renderer/render_frame_impl.h"
+#include "third_party/WebKit/public/platform/WebRect.h"
+#include "third_party/WebKit/public/web/WebElement.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+#include "third_party/WebKit/public/web/WebPluginContainer.h"
 
 namespace content {
 
 namespace {
 
+// 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
+};
+
 // 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;
+
+const char kPowerSaverUnthrottleHistogram[] = "Plugin.PowerSaverUnthrottle";
+
+void RecordUnthrottleMethodMetric(PowerSaverUnthrottleMethod method) {
+  UMA_HISTOGRAM_ENUMERATION(kPowerSaverUnthrottleHistogram, method,
+                            UNTHROTTLE_METHOD_NUM_ITEMS);
+}
 }
 
 PepperPluginInstanceThrottler::PepperPluginInstanceThrottler(
-    const base::Closure& throttle_closure) {
-  DCHECK(!throttle_closure.is_null());
-  base::MessageLoop::current()->PostDelayedTask(
-      FROM_HERE, throttle_closure,
-      base::TimeDelta::FromMilliseconds(kThrottleTimeout));
+    PepperPluginInstanceImpl* instance,
+    const base::Closure& throttle_change_callback)
+    : throttle_change_callback_(throttle_change_callback),
+      power_saver_enabled_(false),
+      is_peripheral_content_(false),
+      plugin_throttled_(false),
+      weak_factory_(this) {
+  DCHECK(instance);
+
+  PluginPowerSaverHelper* power_saver_helper =
+      instance->render_frame()->plugin_power_saver_helper();
+  GURL content_origin = instance->GetPluginURL().GetOrigin();
+  blink::WebRect bounds =
+      instance->container()->element().boundsInViewportSpace();
+
+  bool cross_origin = false;
+  is_peripheral_content_ =
+      instance->module()->name() == kFlashPluginName &&
+      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(
+    const base::Closure& throttle_change_callback,
+    bool power_saver_enabled,
+    bool is_peripheral_content)
+    : throttle_change_callback_(throttle_change_callback),
+      power_saver_enabled_(power_saver_enabled),
+      is_peripheral_content_(is_peripheral_content),
+      plugin_throttled_(false),
+      weak_factory_(this) {}
+
 PepperPluginInstanceThrottler::~PepperPluginInstanceThrottler() {
 }
 
+bool PepperPluginInstanceThrottler::ConsumeInputEvent(
+    const blink::WebInputEvent& event) {
+  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 false;
+}
+
+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