Throttle rendering pipeline for invisible iframes

Source/core/page/PageAnimator.cpp

Index: Source/core/page/PageAnimator.cpp
diff --git a/Source/core/page/PageAnimator.cpp b/Source/core/page/PageAnimator.cpp
index 93b0e21b80b05b9b7dfee899b61685aae28cf4b0..e623e8d0858851dfd83a4a174ff0280339755686 100644
--- a/Source/core/page/PageAnimator.cpp
+++ b/Source/core/page/PageAnimator.cpp
@@ -39,8 +39,12 @@ void PageAnimator::serviceScriptedAnimations(double monotonicAnimationStartTime)
 
     WillBeHeapVector<RefPtrWillBeMember<Document>> documents;
     for (Frame* frame = m_page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
-        if (frame->isLocalFrame())
-            documents.append(toLocalFrame(frame)->document());
+        if (!frame->isLocalFrame())
+            continue;
+        LocalFrame* localFrame = toLocalFrame(frame);
+        if (localFrame->view() && localFrame->view()->shouldThrottleRenderingPipeline())
+            continue;

[dstockwell, 2015/09/01 23:52:24]

I think we might want to split out the animation clock update (inside
DocumentAnimations::updateAnimationTimingForAnimationFrame) from below so that
it can still happen here. That would mean that while we don't run the pipeline
when throttled any query of animation state would still reflect correct timing.
If we don't update the clock here the animations will still advance logically
but their timing will be slightly out of sync with RAF.

Really there should be just one AnimationClock per page, but that's somewhat
orthogonal.

[Sami, 2015/09/02 10:46:03]

Making sure the time still advances sounds like a good idea. I'll look into
doing that.

+        documents.append(localFrame->document());
     }
 
     for (auto& document : documents) {
@@ -91,7 +95,7 @@ void PageAnimator::updateLayoutAndStyleForPainting(LocalFrame* rootFrame)
 
     // setFrameRect may have the side-effect of causing existing page layout to
     // be invalidated, so layout needs to be called last.
-    view->updateAllLifecyclePhases();
+    view->updateAllLifecyclePhases(FrameView::LifecycleThrottlingMode::Allow);
 }
 
 }