Move content's a plugin, ppapi_plugin, utility, and worker subdirectories to the content namespace.

content/worker/websharedworkerclient_proxy.h

Index: content/worker/websharedworkerclient_proxy.h
===================================================================
--- content/worker/websharedworkerclient_proxy.h	(revision 163080)
+++ content/worker/websharedworkerclient_proxy.h	(working copy)
@@ -17,6 +17,8 @@
 class WebFrame;
 }
 
+namespace content {
+
 class SharedWorkerDevToolsAgent;
 class WebSharedWorkerStub;
 
@@ -98,4 +100,6 @@
   DISALLOW_COPY_AND_ASSIGN(WebSharedWorkerClientProxy);
 };
 
+}  // namespace content
+
 #endif  // CONTENT_WORKER_WEBWORKERCLIENT_PROXY_H_