Add DidSaveScrollOrScaleState flag to prevent restoreScrollPositionAndViewState restore from default

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 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:
@@ skipping 185 matching lines @@
                                        SameDocumentNavigationSource,
                                        PassRefPtr<SerializedScriptValue>,
                                        HistoryScrollRestorationType,
                                        FrameLoadType,
                                        Document*);
 
   HistoryItem* currentItem() const { return m_currentItem.get(); }
   void saveScrollState();
 
   void restoreScrollPositionAndViewState();
+  void setScrollFromNavigation(LoadStartType = NavigationToDifferentDocument);

[majidvp, 2017/01/24 21:53:52]

The default argument here does not see worth the readability cost.
I suggest not having a default arg.

I think the Google C++ guideline suggests using default args when
the case for not using default is rare. But here the call site
are so few which suggests it is not worth it to me.

https://google.github.io/styleguide/cppguide.html#Default_Arguments

 
   bool shouldContinueForNavigationPolicy(const ResourceRequest&,
                                          const SubstituteData&,
                                          DocumentLoader*,
                                          ContentSecurityPolicyDisposition,
                                          NavigationType,
                                          NavigationPolicy,
                                          bool shouldReplaceCurrentEntry,
                                          bool isClientRedirect,
                                          HTMLFormElement*);
@@ skipping 106 matching lines @@
   SandboxFlags m_forcedSandboxFlags;
 
   bool m_dispatchingDidClearWindowObjectInMainWorld;
   bool m_protectProvisionalLoader;
   bool m_isNavigationHandledByClient;
 };
 
 }  // namespace blink
 
 #endif  // FrameLoader_h