Reset VisualViewport position after same page navigation

third_party/WebKit/Source/core/page/Page.cpp

Index: third_party/WebKit/Source/core/page/Page.cpp
diff --git a/third_party/WebKit/Source/core/page/Page.cpp b/third_party/WebKit/Source/core/page/Page.cpp
index fe3e99ea8e0f9a28f94f496c9aba209c8ad98917..a5fa749cea263a6e18c4c61f819f0e9c28fef445 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -436,6 +436,11 @@ void Page::didCommitLoad(LocalFrame* frame)
         useCounter().didCommitLoad();
         deprecation().clearSuppression();
         frameHost().visualViewport().sendUMAMetrics();
+
+        // Need to reset visual viewport position here since before commit load we would update the previous history item,
+        // Page::didCommitLoad is called after a new history item is created in FrameLoader.
+        // fix for crbug.com/642279
+        frameHost().visualViewport().setScrollPosition(DoublePoint(), ProgrammaticScroll);
         m_hostsUsingFeatures.updateMeasurementsAndClear();
         UserGestureIndicator::clearProcessedUserGestureSinceLoad();
     }