Add DidSaveScrollOrScaleState flag to prevent restoreScrollPositionAndViewState restore from default

third_party/WebKit/Source/core/loader/FrameLoader.cpp

Index: third_party/WebKit/Source/core/loader/FrameLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameLoader.cpp b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
index 26bd2f95c92e404ed37be2e1c80177c58efb2a69..3f62008d853e5726fe1ca61f37795fa197d8e713 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -36,6 +36,7 @@
 
 #include "core/loader/FrameLoader.h"
 
+#include <memory>
 #include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/SerializedScriptValue.h"
@@ -102,7 +103,6 @@
 #include "wtf/AutoReset.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/WTFString.h"
-#include <memory>
 
 using blink::WebURLRequest;
 
@@ -421,6 +421,8 @@ void FrameLoader::setHistoryItemStateForCommit(
     return;
   m_currentItem->setDocumentSequenceNumber(oldItem->documentSequenceNumber());
   m_currentItem->setScrollOffset(oldItem->getScrollOffset());
+  m_currentItem->setDidSaveScrollOrScaleState(
+      oldItem->didSaveScrollOrScaleState());
   m_currentItem->setVisualViewportScrollOffset(
       oldItem->visualViewportScrollOffset());
   m_currentItem->setPageScaleFactor(oldItem->pageScaleFactor());
@@ -1414,6 +1416,8 @@ void FrameLoader::restoreScrollPositionAndViewStateForLoadType(
   }
   if (!needsHistoryItemRestore(loadType))
     return;
+  if (!m_currentItem->didSaveScrollOrScaleState())
+    return;
 
   bool shouldRestoreScroll =
       m_currentItem->scrollRestorationType() != ScrollRestorationManual;