DevTools: Gracefully ignore unknown variable scopes.

Source/core/inspector/JavaScriptCallFrame.cpp

Index: Source/core/inspector/JavaScriptCallFrame.cpp
diff --git a/Source/core/inspector/JavaScriptCallFrame.cpp b/Source/core/inspector/JavaScriptCallFrame.cpp
index ff6da63c7d9765e8fee7688fd5bcd95e3aeef7bb..b46137979e0fae6a1ffd14eb39891318e967b97b 100644
--- a/Source/core/inspector/JavaScriptCallFrame.cpp
+++ b/Source/core/inspector/JavaScriptCallFrame.cpp
@@ -122,7 +122,9 @@ v8::Handle<v8::Value> JavaScriptCallFrame::scopeChain() const
 
 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();
 }