Add/improve tracing in navigation.

content/browser/site_instance_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/site_instance_impl.h"
 
 #include "base/command_line.h"
 #include "content/browser/browsing_instance.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/frame_host/debug_urls.h"
@@ skipping 102 matching lines @@
     process_->AddObserver(this);
 
     // If we are using process-per-site, we need to register this process
     // for the current site so that we can find it again.  (If no site is set
     // at this time, we will register it in SetSite().)
     if (use_process_per_site) {
       RenderProcessHostImpl::RegisterProcessHostForSite(browser_context,
                                                         process_, site_);
     }
 
+    TRACE_EVENT2("navigation", "SiteInstanceImpl::GetProcess",
+                 "site id", id_, "process id", process_->GetID());
     GetContentClient()->browser()->SiteInstanceGotProcess(this);
 
     if (has_site_)
       LockToOrigin();
   }
   DCHECK(process_);
 
   return process_;
 }
 
 void SiteInstanceImpl::SetSite(const GURL& url) {
+  TRACE_EVENT2("navigation", "SiteInstanceImpl::SetSite",
+               "site id", id_, "url", url.possibly_invalid_spec());
   // A SiteInstance's site should not change.
   // TODO(creis): When following links or script navigations, we can currently
   // render pages from other sites in this SiteInstance.  This will eventually
   // be fixed, but until then, we should still not set the site of a
   // SiteInstance more than once.
   DCHECK(!has_site_);
 
   // Remember that this SiteInstance has been used to load a URL, even if the
   // URL is invalid.
   has_site_ = true;
@@ skipping 197 matching lines @@
       *base::CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kEnableStrictSiteIsolation) ||
       command_line.HasSwitch(switches::kSitePerProcess)) {
     ChildProcessSecurityPolicyImpl* policy =
         ChildProcessSecurityPolicyImpl::GetInstance();
     policy->LockToOrigin(process_->GetID(), site_);
   }
 }
 
 }  // namespace content