Check |m_inspectedFrames| in InspectorNetworkAgent to avoid crashes.

third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp

Index: third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
diff --git a/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp b/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
index 2aab6c337a23b6a80b2a8073bb909f474969d67f..cb6d54fe2ef0545ad00eab3b846b1683fdd6a428 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
@@ -987,6 +987,10 @@ void InspectorNetworkAgent::didFinishXHRInternal(ExecutionContext* context,
 
 void InspectorNetworkAgent::willStartFetch(ThreadableLoaderClient* client) {
   DCHECK(!m_pendingRequest);
+  // The mechanism of documentThreadableLoaderStartedLoadingForClient() doesn't
+  // work when fetch() is called in the worker thread.
+  if (!m_inspectedFrames)
+    return;
   m_pendingRequest = client;
   m_pendingRequestType = InspectorPageAgent::FetchResource;
 }
@@ -1016,6 +1020,10 @@ void InspectorNetworkAgent::didFinishFetch(ExecutionContext* context,
 void InspectorNetworkAgent::willSendEventSourceRequest(
     ThreadableLoaderClient* eventSource) {
   DCHECK(!m_pendingRequest);
+  // The mechanism of documentThreadableLoaderStartedLoadingForClient() doesn't
+  // work when EventSource is used in the worker thread.
+  if (!m_inspectedFrames)
+    return;
   m_pendingRequest = eventSource;
   m_pendingRequestType = InspectorPageAgent::EventSourceResource;
 }
@@ -1443,7 +1451,9 @@ Response InspectorNetworkAgent::setCacheDisabled(bool cacheDisabled) {
   // We should extract network cache state into a global entity which can be
   // queried from FrameLoader and other places.
   m_state->setBoolean(NetworkAgentState::cacheDisabled, cacheDisabled);
-  if (cacheDisabled)
+  // Check |m_inspectedFrames| because we can't touch memoryCache from the
+  // worker thread.
+  if (cacheDisabled && m_inspectedFrames)
     memoryCache()->evictResources();
   return Response::OK();
 }