Plugin Power Saver: Make PPS work well with prerendered pages.

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_thread.h"
 #include "content/renderer/pepper/pepper_plugin_instance_impl.h"
-#include "content/renderer/pepper/pepper_webplugin_impl.h"
 #include "content/renderer/render_frame_impl.h"
 #include "ppapi/shared_impl/ppapi_constants.h"
 #include "ppapi/shared_impl/scoped_pp_var.h"
 #include "ppapi/shared_impl/var.h"
 #include "third_party/WebKit/public/platform/WebRect.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "third_party/WebKit/public/web/WebPluginParams.h"
 #include "ui/gfx/color_utils.h"
 #include "url/gurl.h"
 
 namespace content {
 
 namespace {
 
 // 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;
 
 // When plugin audio is throttled, the plugin will sometimes stop generating
 // video frames. We use this timeout to prevent waiting forever for a good
 // poster image. Chosen arbitrarily.
 const int kAudioThrottledFrameTimeoutMilliseconds = 500;
 
+class PowerSaverTestPluginDelegate : public PluginInstanceThrottler::Observer {
+ public:
+  explicit PowerSaverTestPluginDelegate(
+      const PluginInstanceThrottlerImpl* throttler)
+      : throttler_(throttler) {}
+
+  virtual ~PowerSaverTestPluginDelegate() {}
+
+ private:
+  void OnThrottleStateChange() override {
+    if (throttler_->GetWebPlugin() && throttler_->GetWebPlugin()->instance()) {
+      throttler_->GetWebPlugin()->instance()->HandleMessage(ppapi::ScopedPPVar(
+          ppapi::ScopedPPVar::PassRef(),
+          ppapi::StringVar::StringToPPVar("throttleStatusChange")));
+    }
+  }
+
+  void OnPeripheralStateChange() override {
+    if (throttler_->GetWebPlugin() && throttler_->GetWebPlugin()->instance()) {
+      throttler_->GetWebPlugin()->instance()->HandleMessage(ppapi::ScopedPPVar(
+          ppapi::ScopedPPVar::PassRef(),
+          ppapi::StringVar::StringToPPVar("peripheralStatusChange")));
+    }
+  }
+
+  void OnThrottlerDestroyed() override { delete this; }
+
+  // Non-owning pointer.
+  const PluginInstanceThrottlerImpl* const throttler_;
+};
+
 }  // namespace
 
 // static
 const int PluginInstanceThrottlerImpl::kMaximumFramesToExamine = 150;
 
 // static
 scoped_ptr<PluginInstanceThrottler> PluginInstanceThrottler::Create() {
   return make_scoped_ptr(new PluginInstanceThrottlerImpl);
 }
 
@@ skipping 45 matching lines @@
 
 void PluginInstanceThrottlerImpl::MarkPluginEssential(
     PowerSaverUnthrottleMethod method) {
   if (state_ == THROTTLER_STATE_MARKED_ESSENTIAL)
     return;
 
   bool was_throttled = IsThrottled();
   state_ = THROTTLER_STATE_MARKED_ESSENTIAL;
   RecordUnthrottleMethodMetric(method);
 
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnPeripheralStateChange());
+
   if (was_throttled)
     FOR_EACH_OBSERVER(Observer, observer_list_, OnThrottleStateChange());
-
-  // Notify the Power Saver test plugin of a peripheral status change.
-  if (web_plugin_ && web_plugin_->instance() &&
-      plugin_module_name_ == ppapi::kPowerSaverTestPluginName) {
-    web_plugin_->instance()->HandleMessage(ppapi::ScopedPPVar(
-        ppapi::ScopedPPVar::PassRef(),
-        ppapi::StringVar::StringToPPVar("peripheralStatusChange")));
-  }
 }
 
 void PluginInstanceThrottlerImpl::SetHiddenForPlaceholder(bool hidden) {
   is_hidden_for_placeholder_ = hidden;
   FOR_EACH_OBSERVER(Observer, observer_list_, OnHiddenForPlaceholder(hidden));
 }
 
-blink::WebPlugin* PluginInstanceThrottlerImpl::GetWebPlugin() const {
+PepperWebPluginImpl* PluginInstanceThrottlerImpl::GetWebPlugin() const {
   DCHECK(web_plugin_);
   return web_plugin_;
 }
 
 const gfx::Size& PluginInstanceThrottlerImpl::GetSize() const {
   return unobscured_size_;
 }
 
 void PluginInstanceThrottlerImpl::NotifyAudioThrottled() {
   audio_throttled_ = true;
   audio_throttled_frame_timeout_.Reset();
 }
 
 void PluginInstanceThrottlerImpl::SetWebPlugin(
     PepperWebPluginImpl* web_plugin) {
   DCHECK(!web_plugin_);
   web_plugin_ = web_plugin;
 }
 
 void PluginInstanceThrottlerImpl::Initialize(
     RenderFrameImpl* frame,
     const GURL& content_origin,
     const std::string& plugin_module_name,
     const gfx::Size& unobscured_size) {
-  plugin_module_name_ = plugin_module_name;
   unobscured_size_ = unobscured_size;
 
   // |frame| may be nullptr in tests.
   if (frame) {
     PluginPowerSaverHelper* helper = frame->plugin_power_saver_helper();
     bool cross_origin_main_content = false;
     if (!helper->ShouldThrottleContent(content_origin, plugin_module_name,
                                        unobscured_size.width(),
                                        unobscured_size.height(),
                                        &cross_origin_main_content)) {
       state_ = THROTTLER_STATE_MARKED_ESSENTIAL;
 
       if (cross_origin_main_content)
         helper->WhitelistContentOrigin(content_origin);
 
       return;
     }
 
+    if (plugin_module_name == ppapi::kPowerSaverTestPluginName) {
+      // Delegate manages its own lifetime.
+      new PowerSaverTestPluginDelegate(this);
+    }

[raymes, 2015/04/30 00:42:07]

It still feels a bit nasty to have the observer added in this file (since we
have test and production code in the same place). Could you perhaps add a
PPB_Testing function which adds this delegate and can be called from your test
plugin?

[tommycli, 2015/04/30 01:27:10]

That's a good idea. Will do that!

+
     // To collect UMAs, register peripheral content even if power saver mode
     // is disabled.
     helper->RegisterPeripheralPlugin(
         content_origin,
         base::Bind(&PluginInstanceThrottlerImpl::MarkPluginEssential,
                    weak_factory_.GetWeakPtr(), UNTHROTTLE_METHOD_BY_WHITELIST));
   }
 }
 
 void PluginInstanceThrottlerImpl::OnImageFlush(const SkBitmap* bitmap) {
@@ skipping 51 matching lines @@
 
     // Release our reference to the underlying pixel data.
     last_received_frame_.reset();
   }
 
   state_ = THROTTLER_STATE_PLUGIN_THROTTLED;
   FOR_EACH_OBSERVER(Observer, observer_list_, OnThrottleStateChange());
 }
 
 }  // namespace content