Add ASSERTs in BidiResolver and RenderBlockLineLayout

Source/core/rendering/RenderBlockLineLayout.cpp

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
  * Copyright (C) 2010 Google Inc. All rights 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.
  *
@@ skipping 1284 matching lines @@
         // The starting position is the beginning of the first run within the isolate that was identified
         // during the earlier call to createBidiRunsForLine. This can be but is not necessarily the
         // first run within the isolate.
         InlineIterator iter = InlineIterator(isolatedInline, startObj, isolatedRun->m_start);
         isolatedResolver.setPositionIgnoringNestedIsolates(iter);
         // We stop at the next end of line; we may re-enter this isolate in the next call to constructBidiRuns().
         // FIXME: What should end and previousLineBrokeCleanly be?
         // rniwa says previousLineBrokeCleanly is just a WinIE hack and could always be false here?
         isolatedResolver.createBidiRunsForLine(endOfRuns, NoVisualOverride, previousLineBrokeCleanly);
 
-        // Note that we do not delete the runs from the resolver.
-        // We're not guaranteed to get any BidiRuns in the previous step. If we don't, we allow the placeholder
-        // itself to be turned into an InlineBox. We can't remove it here without potentially losing track of
-        // the logically last run.
+        ASSERT(isolatedResolver.runs().runCount());
         if (isolatedResolver.runs().runCount())
             bidiRuns.replaceRunWithRuns(isolatedRun, isolatedResolver.runs());
 
         // If we encountered any nested isolate runs, just move them
         // to the top resolver's list for later processing.
         if (!isolatedResolver.isolatedRuns().isEmpty()) {
             topResolver.isolatedRuns().append(isolatedResolver.isolatedRuns());
             currentRoot = isolatedInline;
             restoreIsolatedMidpointStates(topResolver, isolatedResolver);
         }
@@ skipping 2228 matching lines @@
     lineGridBox->alignBoxesInBlockDirection(logicalHeight(), textBoxDataMap, verticalPositionCache);
 
     setLineGridBox(lineGridBox);
 
     // FIXME: If any of the characteristics of the box change compared to the old one, then we need to do a deep dirtying
     // (similar to what happens when the page height changes). Ideally, though, we only do this if someone is actually snapping
     // to this grid.
 }
 
 }