Remove a bunch of pointless null checks in FrameLoaderClientImpl.

third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp

Index: third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp b/third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp
index aa8a964dcc230c17a0ab5f0621d06dfc0a2a1ef9..052d74c5b23415b0a3566acfaaca14d6d2156caa 100644
--- a/third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp
+++ b/third_party/WebKit/Source/web/WebEmbeddedWorkerImpl.cpp
@@ -115,16 +115,12 @@ WebEmbeddedWorkerImpl::~WebEmbeddedWorkerImpl() {
   runningWorkerInstances().remove(this);
   DCHECK(m_webView);
 
-  // Detach the client before closing the view to avoid getting called back.
-  m_mainFrame->setClient(0);

[dcheng, 2016/10/17 22:33:29]

This breaks the invariant. For now, I've added early returns to the various
WebFrameClient methods implemented by the workers.

-
   if (m_workerGlobalScopeProxy) {
     m_workerGlobalScopeProxy->detach();
     m_workerGlobalScopeProxy.clear();
   }
 
   m_webView->close();
-  m_mainFrame->close();

[dcheng, 2016/10/17 22:33:29]

The default WebFrameClient implementation already does this.

   if (m_loaderProxy)
     m_loaderProxy->detachProvider(this);
 }
@@ -326,17 +322,26 @@ void WebEmbeddedWorkerImpl::loadShadowPage() {
 
 void WebEmbeddedWorkerImpl::willSendRequest(WebLocalFrame* frame,
                                             WebURLRequest& request) {
+  // TODO(dcheng): Investigate not plumbing through load notifications when a
+  // frame is detached.
+  if (m_askedToTerminate)
+    return;
+
   if (m_networkProvider)
     m_networkProvider->willSendRequest(frame->dataSource(), request);
 }
 
 void WebEmbeddedWorkerImpl::didFinishDocumentLoad(WebLocalFrame* frame) {
+  // TODO(dcheng): Investigate not plumbing through load notifications when a
+  // frame is detached.
+  if (m_askedToTerminate)
+    return;
+
   DCHECK(!m_mainScriptLoader);
   DCHECK(!m_networkProvider);
   DCHECK(m_mainFrame);
   DCHECK(m_workerContextClient);
   DCHECK(m_loadingShadowPage);
-  DCHECK(!m_askedToTerminate);
   m_loadingShadowPage = false;
   m_networkProvider =
       wrapUnique(m_workerContextClient->createServiceWorkerNetworkProvider(