Add a histogram for size of the memory used by redirect chain.

content/browser/frame_host/navigation_controller_impl.cc

 // Copyright 2013 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/frame_host/navigation_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"  // Temporary
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "content/browser/browser_url_handler_impl.h"
 #include "content/browser/dom_storage/dom_storage_context_wrapper.h"
 #include "content/browser/dom_storage/session_storage_namespace_impl.h"
 #include "content/browser/frame_host/debug_urls.h"
 #include "content/browser/frame_host/interstitial_page_impl.h"
 #include "content/browser/frame_host/navigation_entry_impl.h"
@@ skipping 797 matching lines @@
   // All committed entries should have nonempty content state so WebKit doesn't
   // get confused when we go back to them (see the function for details).
   DCHECK(params.page_state.IsValid());
   NavigationEntryImpl* active_entry =
       NavigationEntryImpl::FromNavigationEntry(GetLastCommittedEntry());
   active_entry->SetTimestamp(timestamp);
   active_entry->SetHttpStatusCode(params.http_status_code);
   active_entry->SetPageState(params.page_state);
   active_entry->SetRedirectChain(params.redirects);
 
+  // Use histogram to track memory impact of redirect chain because it's now
+  // not cleared for committed entries.
+  size_t redirect_chain_size = 0;
+  for (size_t i = 0; i < params.redirects.size(); ++i) {
+    redirect_chain_size += params.redirects[i].spec().length();
+  }
+  UMA_HISTOGRAM_COUNTS("Navigation.RedirectChainSize", redirect_chain_size);
+
   // Once it is committed, we no longer need to track several pieces of state on
   // the entry.
   active_entry->ResetForCommit();
 
   // The active entry's SiteInstance should match our SiteInstance.
   // TODO(creis): This check won't pass for subframes until we create entries
   // for subframe navigations.
   if (PageTransitionIsMainFrame(params.transition))
     CHECK(active_entry->site_instance() == rfh->GetSiteInstance());
 
@@ skipping 903 matching lines @@
     }
   }
 }
 
 void NavigationControllerImpl::SetGetTimestampCallbackForTest(
     const base::Callback<base::Time()>& get_timestamp_callback) {
   get_timestamp_callback_ = get_timestamp_callback;
 }
 
 }  // namespace content