#0  operator! (this=0x4034000c) at ../Source/WTF/wtf/RefPtr.h:66
  [Error: ../Source/WTF/wtf/RefPtr.h was not found in source tree]
#1  isEmpty (this=0x4034000c) at ../Source/WebCore/dom/SpaceSplitString.h:116
  [Error: ../Source/WebCore/dom/SpaceSplitString.h was not found in source tree]
#2  hasClass (this=0x40340000) at ../Source/WebCore/dom/ElementData.h:107
  [Error: ../Source/WebCore/dom/ElementData.h was not found in source tree]
#3  hasClass (this=0xb94e91b0) at ../Source/WebCore/dom/Element.h:801
  [Error: ../Source/WebCore/dom/Element.h was not found in source tree]
#4  nodeMatchesInlined (testNode=0xb94e91b0, this=0x9fba2570) at ../Source/WebCore/dom/ClassNodeList.h:62
  [Error: ../Source/WebCore/dom/ClassNodeList.h was not found in source tree]
#5  isMatchingElement<WebCore::ClassNodeList> (element=0xb94e91b0, nodeList=0x9fba2570) at ../Source/WebCore/dom/LiveNodeList.cpp:57
  [Error: ../Source/WebCore/dom/LiveNodeList.cpp was not found in source tree]
#6  firstMatchingElement<WebCore::ClassNodeList> (root=..., nodeList=0x9fba2570) at ../Source/WebCore/dom/LiveNodeList.cpp:74
  [Error: ../Source/WebCore/dom/LiveNodeList.cpp was not found in source tree]
#7  WebCore::LiveNodeList::collectionFirst (this=this@entry=0x9fba2570) at ../Source/WebCore/dom/LiveNodeList.cpp:106
  [Error: ../Source/WebCore/dom/LiveNodeList.cpp was not found in source tree]
#8  0xb526a780 in nodeCount (this=0x9fba2580, this=0x9fba2580, collection=...) at ../Source/WebCore/dom/CollectionIndexCache.h:64
  [Error: ../Source/WebCore/dom/CollectionIndexCache.h was not found in source tree]
#9  WebCore::LiveNodeList::length (this=0x9fba2570) at ../Source/WebCore/dom/LiveNodeList.cpp:138
  [Error: ../Source/WebCore/dom/LiveNodeList.cpp was not found in source tree]
#10 0xb5bf06b4 in WebCore::jsNodeListLength (exec=exec@entry=0xa39fff58, slotBase=-18717474880, thisValue=-18717474880) at DerivedSources/WebCore/JSNodeList.cpp:170
  [Error: DerivedSources/WebCore/JSNodeList.cpp was not found in source tree]
#11 0xb48e77cf in getValue (propertyName=..., exec=0xa39fff58, this=0xbf80c530) at ../Source/JavaScriptCore/runtime/JSObject.h:1549
  [Error: ../Source/JavaScriptCore/runtime/JSObject.h was not found in source tree]
#12 JSC::JSValue::get (this=0xbf80c528, exec=0xa39fff58, propertyName=..., slot=...) at ../Source/JavaScriptCore/runtime/JSCJSValueInlines.h:670
  [Error: ../Source/JavaScriptCore/runtime/JSCJSValueInlines.h was not found in source tree]
#13 0xb4a516de in JSC::LLInt::llint_slow_path_get_by_id (exec=0xa39fff58, pc=0x9c35b060) at ../Source/JavaScriptCore/llint/LLIntSlowPaths.cpp:527
  [Error: ../Source/JavaScriptCore/llint/LLIntSlowPaths.cpp was not found in source tree]
#14 0xb4a5b73e in llint_op_get_by_id () from /tmp/apport_sandbox_jcdNOM/usr/lib/i386-linux-gnu/libjavascriptcoregtk-1.0.so.0
#15 0xa39fff58 in ?? ()