Fix crash when when detecting if LocalFrame is main frame

Source/core/inspector/InspectorTraceEvents.cpp

Index: Source/core/inspector/InspectorTraceEvents.cpp
diff --git a/Source/core/inspector/InspectorTraceEvents.cpp b/Source/core/inspector/InspectorTraceEvents.cpp
index 46e5b6f31a6246f0e643c991abc0fe2fde30c370..76db2e8f452d529cf586dd3770eca5d81d1db990 100644
--- a/Source/core/inspector/InspectorTraceEvents.cpp
+++ b/Source/core/inspector/InspectorTraceEvents.cpp
@@ -273,7 +273,7 @@ PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorMarkLoadEvent::data(Lo
 {
     RefPtr<TracedValue> value = TracedValue::create();
     value->setString("frame", toHexString(frame));
-    bool isMainFrame = frame && frame->page()->mainFrame() == frame;
+    bool isMainFrame = frame && frame->isMainFrame();
     value->setBoolean("isMainFrame", isMainFrame);
     return value;
 }