DevTools: fix crash in ClientMessageLoopAdapter::run

Source/core/inspector/MainThreadDebugger.cpp

Index: Source/core/inspector/MainThreadDebugger.cpp
diff --git a/Source/core/inspector/MainThreadDebugger.cpp b/Source/core/inspector/MainThreadDebugger.cpp
index de83a3ecac8bc236b833a6dab867ac92e2d06214..ce80c771538cea3f3400c21c732bede2a2f96bf7 100644
--- a/Source/core/inspector/MainThreadDebugger.cpp
+++ b/Source/core/inspector/MainThreadDebugger.cpp
@@ -124,6 +124,9 @@ void MainThreadDebugger::interruptMainThreadAndRun(PassOwnPtr<InspectorTaskRunne
 void MainThreadDebugger::runMessageLoopOnPause(v8::Local<v8::Context> context)
 {
     LocalFrame* frame = retrieveFrameWithGlobalObjectCheck(context);
+    // Do not pause in Context of detached frame.
+    if (!frame)
+        return;
     LocalFrame* pausedFrame = frame->localFrameRoot();
     // Wait for continue or step command.
     m_clientMessageLoop->run(pausedFrame);