Remove all but one use of WeakPtrFactory::DetachFromThread

net/proxy/dhcp_proxy_script_adapter_fetcher_win.cc

Index: net/proxy/dhcp_proxy_script_adapter_fetcher_win.cc
diff --git a/net/proxy/dhcp_proxy_script_adapter_fetcher_win.cc b/net/proxy/dhcp_proxy_script_adapter_fetcher_win.cc
index 8a405a78d86ef423516c8fd0978833699fbc20d0..2b49b9430dbc4cf1b8986c5ac0fc2a5fe94f15ca 100644
--- a/net/proxy/dhcp_proxy_script_adapter_fetcher_win.cc
+++ b/net/proxy/dhcp_proxy_script_adapter_fetcher_win.cc
@@ -41,11 +41,6 @@ DhcpProxyScriptAdapterFetcher::DhcpProxyScriptAdapterFetcher(
 
 DhcpProxyScriptAdapterFetcher::~DhcpProxyScriptAdapterFetcher() {
   Cancel();
-
-  // The WeakPtr we passed to the worker thread may be destroyed on the
-  // worker thread.  This detaches any outstanding WeakPtr state from
-  // the current thread.
-  base::SupportsWeakPtr<DhcpProxyScriptAdapterFetcher>::DetachFromThread();
 }
 
 void DhcpProxyScriptAdapterFetcher::Fetch(