Throttle rendering pipeline for invisible iframes

Source/core/page/PageAnimator.cpp

 // 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 "config.h"
 #include "core/page/PageAnimator.h"
 
 #include "core/animation/DocumentAnimations.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 21 matching lines @@
     visitor->trace(m_page);
 }
 
 void PageAnimator::serviceScriptedAnimations(double monotonicAnimationStartTime)
 {
     RefPtrWillBeRawPtr<PageAnimator> protector(this);
     TemporaryChange<bool> servicing(m_servicingAnimations, true);
 
     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) {
         if (document->view()) {
             document->view()->scrollableArea()->serviceScrollAnimations(monotonicAnimationStartTime);
 
             if (const FrameView::ScrollableAreaSet* animatingScrollableAreas = document->view()->animatingScrollableAreas()) {
                 // Iterate over a copy, since ScrollableAreas may deregister
                 // themselves during the iteration.
                 Vector<ScrollableArea*> animatingScrollableAreasCopy;
@@ skipping 30 matching lines @@
 }
 
 void PageAnimator::updateLayoutAndStyleForPainting(LocalFrame* rootFrame)
 {
     RefPtrWillBeRawPtr<FrameView> view = rootFrame->view();
 
     TemporaryChange<bool> servicing(m_updatingLayoutAndStyleForPainting, true);
 
     // 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);
 }
 
 }