Cleanup: Remove WeakPtr usage in WebSharedWorkerImpl

public/web/WebSharedWorker.h

Index: public/web/WebSharedWorker.h
diff --git a/public/web/WebSharedWorker.h b/public/web/WebSharedWorker.h
index a081096ef742778d02cc77e715e2d1bdca92d85d..407d3d1d2222485b90ae1cbcf22a25b49a954714 100644
--- a/public/web/WebSharedWorker.h
+++ b/public/web/WebSharedWorker.h
@@ -44,7 +44,9 @@ class WebURL;
 // This is the interface to a SharedWorker thread.
 class WebSharedWorker {
 public:
-    // Invoked from the worker thread to instantiate a WebSharedWorker that interacts with the WebKit worker components.
+    // Instantiate a WebSharedWorker that interacts with the shared worker.
+    // WebSharedWorkerClient given here must outlive or have the identical
+    // lifetime as this instance.
     BLINK_EXPORT static WebSharedWorker* create(WebSharedWorkerClient*);
 
     virtual void startWorkerContext(
@@ -56,12 +58,9 @@ public:
     // Sends a connect event to the SharedWorker context.
     virtual void connect(WebMessagePortChannel*) = 0;
 
-    // Invoked to shutdown the worker when there are no more associated documents.
+    // Invoked to shutdown the worker when there are no more associated documents. This eventually deletes this instance.
     virtual void terminateWorkerContext() = 0;
 
-    // Notification when the WebCommonWorkerClient is destroyed.
-    virtual void clientDestroyed() = 0;
-
     virtual void pauseWorkerContextOnStart() = 0;
     virtual void attachDevTools(const WebString& hostId) = 0;
     virtual void reattachDevTools(const WebString& hostId, const WebString& savedState) = 0;