Add ASSERTs in BidiResolver and RenderBlockLineLayout

Source/platform/text/BidiResolver.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008 Apple Inc.  All right reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 181 matching lines @@
     void setContext(PassRefPtr<BidiContext> c) { m_status.context = c; }
 
     void setLastDir(WTF::Unicode::Direction lastDir) { m_status.last = lastDir; }
     void setLastStrongDir(WTF::Unicode::Direction lastStrongDir) { m_status.lastStrong = lastStrongDir; }
     void setEorDir(WTF::Unicode::Direction eorDir) { m_status.eor = eorDir; }
 
     WTF::Unicode::Direction dir() const { return m_direction; }
     void setDir(WTF::Unicode::Direction d) { m_direction = d; }
 
     const BidiStatus& status() const { return m_status; }
-    void setStatus(const BidiStatus s) { m_status = s; }
+    void setStatus(const BidiStatus s)
+    {
+        ASSERT(s.context);
+        m_status = s;
+    }
 
     MidpointState<Iterator>& midpointState() { return m_midpointState; }
 
     // The current algorithm handles nested isolates one layer of nesting at a time.
     // But when we layout each isolated span, we will walk into (and ignore) all
     // child isolated spans.
     void enterIsolate() { m_nestedIsolateCount++; }
     void exitIsolate() { ASSERT(m_nestedIsolateCount >= 1); m_nestedIsolateCount--; }
     bool inIsolate() const { return m_nestedIsolateCount; }
 
@@ skipping 764 matching lines @@
 template<class Iterator, class Run>
 MidpointState<Iterator> BidiResolver<Iterator, Run>::midpointStateForIsolatedRun(Run* run)
 {
     return m_midpointStateForIsolatedRun.take(run);
 }
 
 
 } // namespace WebCore
 
 #endif // BidiResolver_h