Re-land^2 WebVR compositor bypass via BrowserMain context + mailbox

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 3031 matching lines @@
       DCHECK(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled() ||
              lifecycle().state() >= DocumentLifecycle::CompositingClean);
 
       m_frame->host()->globalRootScrollerController().didUpdateCompositing();
 
       if (targetState >= DocumentLifecycle::PrePaintClean) {
         if (!RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
           invalidateTreeIfNeededRecursive();
 
         if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
-          if (view.compositor()->inCompositingMode())
+          if (view.compositor()->inCompositingMode() && isSelfVisible())
             scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
         }
 
         if (LocalFrame* localFrame = m_frame->localFrameRoot()) {
           // This is needed since, at present, the ScrollingCoordinator doesn't
           // send rects for oopif sub-frames.
           // TODO(wjmaclean): Remove this pathway when ScrollingCoordinator
           // operates on a per-frame basis. https://crbug.com/680606
           frame().page()->chromeClient().updateTouchRectsForSubframeIfNecessary(
               localFrame);
@@ skipping 2152 matching lines @@
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 LayoutUnit FrameView::caretWidth() const {
   return LayoutUnit(getHostWindow()->windowToViewportScalar(1));
 }
 
 }  // namespace blink