Plugin Power Saver: Add UI Overlay to throttled plugin using placeholder.

content/renderer/pepper/plugin_instance_throttler_impl.cc

Index: content/renderer/pepper/plugin_instance_throttler_impl.cc
diff --git a/content/renderer/pepper/plugin_instance_throttler_impl.cc b/content/renderer/pepper/plugin_instance_throttler_impl.cc
index a95f6db47aef47039b6c9696a87917f53b36f5da..05303d5853aeb0624b3701aaf6a441e2c9289ee1 100644
--- a/content/renderer/pepper/plugin_instance_throttler_impl.cc
+++ b/content/renderer/pepper/plugin_instance_throttler_impl.cc
@@ -60,6 +60,7 @@ PluginInstanceThrottlerImpl::PluginInstanceThrottlerImpl(
     : state_(power_saver_enabled ? POWER_SAVER_ENABLED_AWAITING_KEYFRAME
                                  : POWER_SAVER_DISABLED),
       consecutive_interesting_frames_(0),
+      keyframe_extraction_timed_out_(false),
       weak_factory_(this) {
   // To collect UMAs, register peripheral content even if power saver disabled.
   if (frame) {
@@ -71,13 +72,15 @@ PluginInstanceThrottlerImpl::PluginInstanceThrottlerImpl(
 
   if (power_saver_enabled) {
     base::MessageLoop::current()->PostDelayedTask(
-        FROM_HERE, base::Bind(&PluginInstanceThrottlerImpl::EngageThrottle,
-                              weak_factory_.GetWeakPtr()),
+        FROM_HERE,
+        base::Bind(&PluginInstanceThrottlerImpl::TimeoutKeyframeExtraction,
+                   weak_factory_.GetWeakPtr()),
         base::TimeDelta::FromMilliseconds(kThrottleTimeout));
   }
 }
 
 PluginInstanceThrottlerImpl::~PluginInstanceThrottlerImpl() {
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnThrottlerDestroyed());
   if (state_ != PLUGIN_INSTANCE_MARKED_ESSENTIAL)
     RecordUnthrottleMethodMetric(UNTHROTTLE_METHOD_NEVER);
 }
@@ -118,8 +121,11 @@ void PluginInstanceThrottlerImpl::OnImageFlush(const SkBitmap* bitmap) {
   else
     consecutive_interesting_frames_ = 0;
 
-  if (consecutive_interesting_frames_ >= kMinimumConsecutiveInterestingFrames)
+  if (keyframe_extraction_timed_out_ ||
+      consecutive_interesting_frames_ >= kMinimumConsecutiveInterestingFrames) {
+    FOR_EACH_OBSERVER(Observer, observer_list_, OnKeyframeExtracted(bitmap));

[groby-ooo-7-16, 2015/01/30 02:22:44]

Do we expect multiple observers? 

[tommycli, 2015/01/30 17:02:40]

In general, yes. For this particular call, there's currently only one observer.
The other observers have noop stub methods.

     EngageThrottle();
+  }
 }
 
 bool PluginInstanceThrottlerImpl::ConsumeInputEvent(
@@ -150,4 +156,9 @@ void PluginInstanceThrottlerImpl::EngageThrottle() {
   FOR_EACH_OBSERVER(Observer, observer_list_, OnThrottleStateChange());
 }
 
+void PluginInstanceThrottlerImpl::TimeoutKeyframeExtraction() {
+  DCHECK(!keyframe_extraction_timed_out_);

[groby-ooo-7-16, 2015/01/30 02:22:44]

Why do we care about this as a precondition? Will anything go wrong if this is
called twice?

[tommycli, 2015/01/30 17:02:40]

Done.

+  keyframe_extraction_timed_out_ = true;
+}
+
 }  // namespace content