DevTools: retain DTAH in all the targets to match their life time.

content/browser/devtools/devtools_agent_host_impl.cc

Index: content/browser/devtools/devtools_agent_host_impl.cc
diff --git a/content/browser/devtools/devtools_agent_host_impl.cc b/content/browser/devtools/devtools_agent_host_impl.cc
index a23f00b5667a78b75d9b899a6b6392ed057bb703..a036c4c614c6b45e42d75fe5ab43feb7c1d980f3 100644
--- a/content/browser/devtools/devtools_agent_host_impl.cc
+++ b/content/browser/devtools/devtools_agent_host_impl.cc
@@ -82,13 +82,6 @@ DevToolsAgentHost::List DevToolsAgentHost::GetOrCreateAll() {
   return result;
 }
 
-// static
-void DevToolsAgentHost::DiscoverAllHosts(const DiscoveryCallback& callback) {
-  DevToolsManager* manager = DevToolsManager::GetInstance();
-  if (!manager->delegate() || !manager->delegate()->DiscoverTargets(callback))
-    callback.Run(DevToolsAgentHost::GetOrCreateAll());
-}
-
 // Called on the UI thread.
 // static
 scoped_refptr<DevToolsAgentHost> DevToolsAgentHost::GetForWorker(