Remove extra calls of didMeaningfulLayout() during the same navigation

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 3972 matching lines @@
 void WebViewImpl::setSelectionColors(unsigned activeBackgroundColor,
                                      unsigned activeForegroundColor,
                                      unsigned inactiveBackgroundColor,
                                      unsigned inactiveForegroundColor) {
 #if USE(DEFAULT_RENDER_THEME)
     LayoutThemeDefault::setSelectionColors(activeBackgroundColor, activeForegroundColor, inactiveBackgroundColor, inactiveForegroundColor);
     LayoutTheme::theme().platformColorsDidChange();
 #endif
 }
 
-void WebViewImpl::didCommitLoad(bool isNewNavigation, bool isNavigationWithinPage)
+void WebViewImpl::didCommitLoad(HistoryCommitType commitType, bool isNavigationWithinPage)
 {
     if (!isNavigationWithinPage) {
-        m_shouldDispatchFirstVisuallyNonEmptyLayout = true;
-        m_shouldDispatchFirstLayoutAfterFinishedParsing = true;
-        m_shouldDispatchFirstLayoutAfterFinishedLoading = true;
+        if (commitType == StandardCommit || commitType == BackForwardCommit) {
+            m_shouldDispatchFirstVisuallyNonEmptyLayout = true;
+            m_shouldDispatchFirstLayoutAfterFinishedParsing = true;
+            m_shouldDispatchFirstLayoutAfterFinishedLoading = true;
+        }
 
-        if (isNewNavigation) {
+        if (commitType == StandardCommit) {
+            // A new session history item should be created for this load.
             pageScaleConstraintsSet().setNeedsReset(true);
             m_pageImportanceSignals.onCommitLoad();
         }
     }
 
     // Give the visual viewport's scroll layer its initial size.
     page()->frameHost().visualViewport().mainFrameDidChangeSize();
 
     // Make sure link highlight from previous page is cleared.
     m_linkHighlights.clear();
@@ skipping 280 matching lines @@
         bool visible = page()->visibilityState() == PageVisibilityStateVisible;
         m_layerTreeView->setVisible(visible);
     } else {
         m_rootGraphicsLayer = nullptr;
         m_rootLayer = nullptr;
         // This means that we're transitioning to a new page. Suppress
         // commits until Blink generates invalidations so we don't
         // attempt to paint too early in the next page load.
         m_layerTreeView->setDeferCommits(true);
         m_layerTreeView->clearRootLayer();
+
+        // didMeaningfulLayout() should be dispatched again.
+        m_shouldDispatchFirstVisuallyNonEmptyLayout = true;

[dglazkov, 2016/01/15 19:41:48]

Interesting! This is a partial revert of
https://codereview.chromium.org/1380363005/, which indeed caused this problem.
We shouldn't need it though if we ignore didCommitLoad from child frames, right?

[wychen, 2016/01/15 22:31:02]

This is still needed, for cases like refreshing, or redirection.

[dglazkov, 2016/01/15 22:36:43]

Both refresh and redirect will result in a new didCommitLoad call: they both
signal destroying and re-creating a new main frame doc, which will trigger the
load and the didCommitLoad. Are there any others we could be forgetting?

[wychen, 2016/01/21 01:47:52]

Ah. I filtered out HistoryInertCommit in this patch set (#1), so I needed these.
They are removed now.

+        m_shouldDispatchFirstLayoutAfterFinishedParsing = true;
+        m_shouldDispatchFirstLayoutAfterFinishedLoading = true;
+
         visualViewport.clearLayersForTreeView(m_layerTreeView);
     }
 }
 
 void WebViewImpl::invalidateRect(const IntRect& rect)
 {
     if (m_layerTreeView)
         updateLayerTreeViewport();
     else if (m_client)
         m_client->didInvalidateRect(rect);
@@ skipping 315 matching lines @@
 void WebViewImpl::detachPaintArtifactCompositor()
 {
     if (!m_layerTreeView)
         return;
 
     m_layerTreeView->setDeferCommits(true);
     m_layerTreeView->clearRootLayer();
 }
 
 } // namespace blink