DevTools: Fix Crash Report - v8::Value::IsInt32.

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 38 matching lines @@
 {
 }
 
 JavaScriptCallFrame* JavaScriptCallFrame::caller()
 {
     if (!m_caller) {
         v8::HandleScope handleScope(m_isolate);
         v8::Handle<v8::Context> debuggerContext = m_debuggerContext.newLocal(m_isolate);
         v8::Context::Scope contextScope(debuggerContext);
         v8::Handle<v8::Value> callerFrame = m_callFrame.newLocal(m_isolate)->Get(v8AtomicString(m_isolate, "caller"));
-        if (!callerFrame->IsObject())
+        if (callerFrame.IsEmpty() || !callerFrame->IsObject())
             return 0;
         m_caller = JavaScriptCallFrame::create(debuggerContext, v8::Handle<v8::Object>::Cast(callerFrame));
     }
     return m_caller.get();
 }
 
 int JavaScriptCallFrame::callV8FunctionReturnInt(const char* name) const
 {
     v8::HandleScope handleScope(m_isolate);
+    v8::Context::Scope contextScope(m_debuggerContext.newLocal(m_isolate));
     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, name)));
     v8::Handle<v8::Value> result = func->Call(callFrame, 0, 0);
-    if (result->IsInt32())
-        return result->Int32Value();
-    return 0;
+    if (result.IsEmpty() || !result->IsInt32())
+        return 0;
+    return result->Int32Value();
 }
 
 String JavaScriptCallFrame::callV8FunctionReturnString(const char* name) const
 {
     v8::HandleScope handleScope(m_isolate);
+    v8::Context::Scope contextScope(m_debuggerContext.newLocal(m_isolate));
     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, name)));
     v8::Handle<v8::Value> result = func->Call(callFrame, 0, 0);
     return toCoreStringWithUndefinedOrNullCheck(result);
 }
 
 int JavaScriptCallFrame::sourceID() const
 {
     return callV8FunctionReturnInt("sourceID");
 }
@@ skipping 43 matching lines @@
 String JavaScriptCallFrame::stepInPositions() const
 {
     return callV8FunctionReturnString("stepInPositions");
 }
 
 bool JavaScriptCallFrame::isAtReturn() const
 {
     v8::HandleScope handleScope(m_isolate);
     v8::Context::Scope contextScope(m_debuggerContext.newLocal(m_isolate));
     v8::Handle<v8::Value> result = m_callFrame.newLocal(m_isolate)->Get(v8AtomicString(m_isolate, "isAtReturn"));
-    if (result->IsBoolean())
-        return result->BooleanValue();
-    return false;
+    if (result.IsEmpty() || !result->IsBoolean())
+        return false;
+    return result->BooleanValue();
 }
 
 v8::Handle<v8::Value> JavaScriptCallFrame::returnValue() const
 {
     return m_callFrame.newLocal(m_isolate)->Get(v8AtomicString(m_isolate, "returnValue"));
 }
 
 v8::Handle<v8::Value> JavaScriptCallFrame::evaluateWithExceptionDetails(const String& expression)
 {
     v8::Handle<v8::Object> callFrame = m_callFrame.newLocal(m_isolate);
@@ skipping 49 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