DevTools: use per-LocalFrame instrumenting agents instead of per-Page ones.

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 63ad11c480ce6ef9fa427e6b306ee8f3a3a88208..87cd97de3182395ecc8f7fb0c60585ba3f44c8b3 100644
--- a/Source/core/inspector/InspectorTraceEvents.cpp
+++ b/Source/core/inspector/InspectorTraceEvents.cpp
@@ -679,11 +679,11 @@ PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorTracingSessionIdForWor
     return value.release();
 }
 
-PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorTracingStartedInPage::data(const String& sessionId, Page* page)
+PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorTracingStartedInFrame::data(const String& sessionId, LocalFrame* frame)
 {
     RefPtr<TracedValue> value = TracedValue::create();
     value->setString("sessionId", sessionId);
-    value->setString("page", toHexString(page));
+    value->setString("page", toHexString(frame));
     return value.release();
 }