Throttle rendering pipeline for invisible iframes

Source/core/layout/compositing/DeprecatedPaintLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 176 matching lines @@
 void updateDescendantDependentFlagsForEntireSubtree(DeprecatedPaintLayer& layer)
 {
     layer.updateDescendantDependentFlags();
 
     for (DeprecatedPaintLayer* child = layer.firstChild(); child; child = child->nextSibling())
         updateDescendantDependentFlagsForEntireSubtree(*child);
 }
 
 void DeprecatedPaintLayerCompositor::updateIfNeededRecursive()
 {
+    FrameView* view = m_layoutView.frameView();
+    if (view->shouldThrottleStyleLayoutAndCompositingUpdates())
+        return;
+
     for (Frame* child = m_layoutView.frameView()->frame().tree().firstChild(); child; child = child->tree().nextSibling()) {
         if (!child->isLocalFrame())
             continue;
         LocalFrame* localFrame = toLocalFrame(child);
         // It's possible for trusted Pepper plugins to force hit testing in situations where
         // the frame tree is in an inconsistent state, such as in the middle of frame detach.
         // TODO(bbudge) Remove this check when trusted Pepper plugins are gone.
         if (localFrame->document()->isActive())
             localFrame->contentLayoutObject()->compositor()->updateIfNeededRecursive();
     }
@@ skipping 24 matching lines @@
     m_layoutView.frameView()->scrollableArea()->updateCompositorScrollAnimations();
     if (const FrameView::ScrollableAreaSet* animatingScrollableAreas = m_layoutView.frameView()->animatingScrollableAreas()) {
         for (ScrollableArea* scrollableArea : *animatingScrollableAreas)
             scrollableArea->updateCompositorScrollAnimations();
     }
 
 #if ENABLE(ASSERT)
     ASSERT(lifecycle().state() == DocumentLifecycle::CompositingClean);
     assertNoUnresolvedDirtyBits();
     for (Frame* child = m_layoutView.frameView()->frame().tree().firstChild(); child; child = child->tree().nextSibling()) {
-        if (child->isLocalFrame())
-            toLocalFrame(child)->contentLayoutObject()->compositor()->assertNoUnresolvedDirtyBits();
+        if (!child->isLocalFrame())
+            continue;
+        LocalFrame* localFrame = toLocalFrame(child);
+        if (FrameView* childView = localFrame->view()) {

[ojan, 2015/09/01 19:56:48]

Nit: Looks like you're going from Frame-->FrameView-->
shouldThrottleStyleLayoutAndCompositingUpdates in a number of places. Maybe add
a shouldThrottleStyleLayoutAndCompositingUpdates to Frame that just passes
through to FrameView (and does the null check of course)? That would make the
calling code a bit simpler.

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

Good idea, done. (I assume you meant LocalFrame instead of Frame).

+            if (childView->shouldThrottleStyleLayoutAndCompositingUpdates())
+                continue;
+        }
+        localFrame->contentLayoutObject()->compositor()->assertNoUnresolvedDirtyBits();
     }
 #endif
 }
 
 void DeprecatedPaintLayerCompositor::setNeedsCompositingUpdate(CompositingUpdateType updateType)
 {
     ASSERT(updateType != CompositingUpdateNone);
     m_pendingUpdateType = std::max(m_pendingUpdateType, updateType);
     page()->animator().scheduleVisualUpdate(m_layoutView.frame());
     lifecycle().ensureStateAtMost(DocumentLifecycle::LayoutClean);
@@ skipping 955 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "LocalFrame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink