Fixes crash when swapping frames

Source/core/loader/FrameLoader.cpp

Index: Source/core/loader/FrameLoader.cpp
diff --git a/Source/core/loader/FrameLoader.cpp b/Source/core/loader/FrameLoader.cpp
index 402242e0aadd008832a7cd86795df725fb65176c..69af303ca74863ce1a52fb74673bd27fda52a282 100644
--- a/Source/core/loader/FrameLoader.cpp
+++ b/Source/core/loader/FrameLoader.cpp
@@ -482,7 +482,7 @@ void FrameLoader::finishedParsing()
     m_progressTracker->finishedParsing();
 
     if (client())
-        client()->dispatchDidFinishDocumentLoad(m_documentLoader->isCommittedButEmpty());
+        client()->dispatchDidFinishDocumentLoad(m_documentLoader ? m_documentLoader->isCommittedButEmpty() : true);
 
     checkCompleted();
 
@@ -1255,7 +1255,7 @@ void FrameLoader::processFragment(const KURL& url, LoadStartType loadStartType)
     // If scroll position is restored from history fragment then we should not override it unless
     // this is a same document reload.
     bool shouldScrollToFragment = (loadStartType == NavigationWithinSameDocument && !isBackForwardLoadType(m_loadType))
-        || !documentLoader()->initialScrollState().didRestoreFromHistory;
+        || (documentLoader() && !documentLoader()->initialScrollState().didRestoreFromHistory);

[Nate Chapin, 2015/08/17 19:20:35]

Is this part actually necessary? I would have thought the FrameView null check
at the top of this function would catch the null DocumentLoader case.

[sky, 2015/08/17 20:32:36]

My first fix was line 485. That fix got me here. So, yes, both were necessary.
The view is non-null. If it were null we wouldn't have gotten here because of
the conditional on 489.

 
     view->processUrlFragment(url, shouldScrollToFragment ?
         FrameView::UrlFragmentScroll : FrameView::UrlFragmentDontScroll);