DevTools: show styles for shadow dom elements

Source/core/inspector/InspectorCSSAgent.cpp

Index: Source/core/inspector/InspectorCSSAgent.cpp
diff --git a/Source/core/inspector/InspectorCSSAgent.cpp b/Source/core/inspector/InspectorCSSAgent.cpp
index 75a4b93b0206a9d50178f2e8871aab94623d78c6..8ae033bb045d2631f530de7126b151370f720eaa 100644
--- a/Source/core/inspector/InspectorCSSAgent.cpp
+++ b/Source/core/inspector/InspectorCSSAgent.cpp
@@ -878,15 +878,19 @@ void InspectorCSSAgent::wasEnabled(PassRefPtr<EnableCallback> callback)
         return;
     }
 
-    // Re-read stylesheets, we know for sure we have content for all of them.
     Vector<InspectorStyleSheet*> styleSheets;
     collectAllStyleSheets(styleSheets);
     for (size_t i = 0; i < styleSheets.size(); ++i)
         m_frontend->styleSheetAdded(styleSheets.at(i)->buildObjectForStyleSheetInfo());
-    if (callback)
-        callback->sendSuccess();
 
+    // More styleSheetAdded events will be generated below.
     m_instrumentingAgents->setInspectorCSSAgent(this);
+    Vector<Document*> documents = m_domAgent->documents();
+    for (Vector<Document*>::iterator it = documents.begin(); it != documents.end(); ++it)
+        (*it)->styleEngine()->updateActiveStyleSheets(FullStyleUpdate);
+
+    if (callback)
+        callback->sendSuccess();
 }
 
 void InspectorCSSAgent::disable(ErrorString*)