Defer ChromeClient::attachRootGraphicsLayer until after compositing update.

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index a14899a44e8bbb407cce2a174f07682c7ebdcd15..8ada9cca4c3fd9c320c92f723a0ceb6f9275ebe8 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -361,6 +361,7 @@ WebViewImpl::WebViewImpl(WebViewClient* client,
       m_suppressNextKeypressEvent(false),
       m_imeAcceptEvents(true),
       m_devToolsEmulator(nullptr),
+      m_needsUpdatePageOverlays(false),
       m_isTransparent(false),
       m_tabsToLinks(false),
       m_layerTreeView(nullptr),
@@ -1997,6 +1998,8 @@ void WebViewImpl::updateAllLifecyclePhases() {
   PageWidgetDelegate::updateAllLifecyclePhases(*m_page,
                                                *mainFrameImpl()->frame());
 
+  // This needs to run after the compositing update.
+  updatePageOverlays();

[bokan, 2017/03/06 16:17:18]

I think there's ways for compositing to be run without going through
WVI::updateAllLifecyclePhases, e.g
FrameView::updateLifecycleToCompositingCleanPlusScrolling is called from
GestureManager::handleGestureTap, is that ok?

[skobes, 2017/03/06 22:44:23]

Done, although doing this from WebViewImpl::layoutUpdated hits a re-entrancy
assertion in FrameView::updateLifecyclePhasesInternal.

It looks like it's sufficient to call it only from setPageOverlayColor, since
this ensures subsequent invocations of PageOverlay::update will see the root
GraphicsLayer.

   if (InspectorOverlay* overlay = inspectorOverlay()) {
     overlay->updateAllLifecyclePhases();
     // TODO(chrishtr): integrate paint into the overlay's lifecycle.
@@ -3682,7 +3685,7 @@ void WebViewImpl::layoutUpdated(WebLocalFrameImpl* webframe) {
   if (view->needsLayout())
     view->layout();
 
-  updatePageOverlays();
+  m_needsUpdatePageOverlays = true;
 
   m_fullscreenController->didUpdateLayout();
   m_client->didUpdateLayout();
@@ -3727,7 +3730,7 @@ void WebViewImpl::setPageOverlayColor(WebColor color) {
 
   m_pageColorOverlay = PageOverlay::create(
       mainFrameImpl(), WTF::makeUnique<ColorOverlay>(color));
-  m_pageColorOverlay->update();
+  m_needsUpdatePageOverlays = true;
 }
 
 WebPageImportanceSignals* WebViewImpl::pageImportanceSignals() {
@@ -4139,12 +4142,15 @@ AnimationWorkletProxyClient* WebViewImpl::createAnimationWorkletProxyClient() {
 }
 
 void WebViewImpl::updatePageOverlays() {
-  if (m_pageColorOverlay)
-    m_pageColorOverlay->update();
-  if (InspectorOverlay* overlay = inspectorOverlay()) {
-    PageOverlay* inspectorPageOverlay = overlay->pageOverlay();
-    if (inspectorPageOverlay)
-      inspectorPageOverlay->update();
+  if (m_needsUpdatePageOverlays) {
+    if (m_pageColorOverlay)
+      m_pageColorOverlay->update();
+    if (InspectorOverlay* overlay = inspectorOverlay()) {
+      PageOverlay* inspectorPageOverlay = overlay->pageOverlay();
+      if (inspectorPageOverlay)
+        inspectorPageOverlay->update();
+    }
+    m_needsUpdatePageOverlays = false;
   }
 }