DevTools: Gracefully ignore unknown variable scopes.

Source/core/inspector/JavaScriptCallFrame.cpp

 /*
  * Copyright (c) 2010, 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 104 matching lines @@
     v8::Handle<v8::Function> func = v8::Handle<v8::Function>::Cast(callFrame->Get(v8AtomicString(m_isolate, "scopeChain")));
     v8::Handle<v8::Array> scopeChain = v8::Handle<v8::Array>::Cast(func->Call(callFrame, 0, 0));
     v8::Handle<v8::Array> result = v8::Array::New(m_isolate, scopeChain->Length());
     for (uint32_t i = 0; i < scopeChain->Length(); i++)
         result->Set(i, scopeChain->Get(i));
     return result;
 }
 
 int JavaScriptCallFrame::scopeType(int scopeIndex) const
 {
-    v8::Handle<v8::Array> scopeType = v8::Handle<v8::Array>::Cast(m_callFrame.newLocal(m_isolate)->Get(v8AtomicString(m_isolate, "scopeType")));
+    v8::Handle<v8::Object> callFrame = m_callFrame.newLocal(m_isolate);
+    v8::Handle<v8::Function> func = v8::Handle<v8::Function>::Cast(callFrame->Get(v8AtomicString(m_isolate, "scopeType")));
+    v8::Handle<v8::Array> scopeType = v8::Handle<v8::Array>::Cast(func->Call(callFrame, 0, 0));
     return scopeType->Get(scopeIndex)->Int32Value();
 }
 
 v8::Handle<v8::Value> JavaScriptCallFrame::thisObject() const
 {
     return m_callFrame.newLocal(m_isolate)->Get(v8AtomicString(m_isolate, "thisObject"));
 }
 
 String JavaScriptCallFrame::stepInPositions() const
 {
@@ skipping 75 matching lines @@
         exceptionDetails->Set(v8::String::NewFromUtf8(isolate, "stackTrace"), v8::Undefined(isolate));
     return exceptionDetails;
 }
 
 void JavaScriptCallFrame::trace(Visitor* visitor)
 {
     visitor->trace(m_caller);
 }
 
 } // namespace blink