Don't reuse HistoryItems for multiple navigations

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 3341 matching lines @@
     if (!page()->mainFrame()->isLocalFrame())
         return;
 
     if (FrameView* frameView = toLocalFrame(page()->mainFrame())->view()) {
         ScrollableArea* scrollableArea = frameView->layoutViewportScrollableArea();
 
         if (scrollableArea->scrollPositionDouble() != DoublePoint::zero())
             scrollableArea->notifyScrollPositionChanged(DoublePoint::zero());
     }
 
-    // Clear out the values for the current history item. This will prevent the history item from clobbering the
-    // value determined during page scale initialization, which may be less than 1.
-    page()->deprecatedLocalMainFrame()->loader().clearScrollPositionAndViewState();
     pageScaleConstraintsSet().setNeedsReset(true);
 
     // Clobber saved scales and scroll offsets.
     if (FrameView* view = page()->deprecatedLocalMainFrame()->document()->view())
         view->cacheCurrentScrollPosition();
 }
 
 void WebViewImpl::performMediaPlayerAction(const WebMediaPlayerAction& action,
                                            const WebPoint& location)
 {
@@ skipping 1030 matching lines @@
 {
     WebGLRenderingContext::forceNextWebGLContextCreationToFail();
 }
 
 void WebViewImpl::forceNextDrawingBufferCreationToFail()
 {
     DrawingBuffer::forceNextDrawingBufferCreationToFail();
 }
 
 } // namespace blink