Add histograms for prerender rel types.

chrome/browser/prerender/prerender_link_manager.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 "chrome/browser/prerender/prerender_link_manager.h"
 
 #include <limits>
 #include <set>
 #include <string>
 #include <utility>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/field_trial.h"
+#include "base/metrics/histogram.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/prerender_messages.h"
 #include "chrome/common/prerender_types.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/session_storage_namespace.h"
@@ skipping 10 matching lines @@
 
 namespace {
 
 bool ShouldStartRelNextPrerenders() {
   const std::string experiment_name =
       base::FieldTrialList::FindFullName("PrerenderRelNextTrial");
 
   return experiment_name.find("Yes") != std::string::npos;
 }
 
-bool ShouldStartPrerender(uint32 rel_types) {
+bool ShouldStartPrerender(const uint32 rel_types) {
   const bool should_start_rel_next_prerenders =
       ShouldStartRelNextPrerenders();
 
   if (rel_types & PrerenderRelTypePrerender) {
     return true;
   } else if (should_start_rel_next_prerenders &&
              (rel_types & PrerenderRelTypeNext) == PrerenderRelTypeNext) {
     return true;
   }
   return false;
 }
 
+COMPILE_ASSERT(PrerenderRelTypePrerender == 0x1,
+               RelTypeHistogramEnum_must_match_PrerenderRelType);
+COMPILE_ASSERT(PrerenderRelTypeNext == 0x2,
+               RelTypeHistogramEnum_must_match_PrerenderRelType);
+enum RelTypeHistogramEnum {

[gavinp, 2013/12/20 19:56:43]

Our coding standard doesn't define an order for translation units, only for
classes. The restriction on ordering is within classes, see
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Declar...
. 

So I moved the enum down here, closer to the histogram reporting functions, for
easier readability. What do you think?

+  RelTypeHistogramEnumNone = 0,
+  RelTypeHistogramEnumPrerender = PrerenderRelTypePrerender,
+  RelTypeHistogramEnumNext = PrerenderRelTypeNext,
+  RelTypeHistogramEnumPrerenderAndNext =
+      PrerenderRelTypePrerender | PrerenderRelTypeNext,
+  RelTypeHistogramEnumMax,
+};
+
+void RecordLinkManagerAdded(const uint32 rel_types) {
+  const uint32 enum_value = rel_types & (RelTypeHistogramEnumMax - 1);
+  UMA_HISTOGRAM_ENUMERATION("Prerender.RelTypesLinkAdded", enum_value,
+                            RelTypeHistogramEnumMax);
+}
+
+void RecordLinkManagerStarting(const uint32 rel_types) {
+  const uint32 enum_value = rel_types & (RelTypeHistogramEnumMax - 1);
+  UMA_HISTOGRAM_ENUMERATION("Prerender.RelTypesLinkStarted", enum_value,
+                            RelTypeHistogramEnumMax);
+}
+
 void Send(int child_id, IPC::Message* raw_message) {
   using content::RenderProcessHost;
   scoped_ptr<IPC::Message> own_message(raw_message);
 
   RenderProcessHost* render_process_host = RenderProcessHost::FromID(child_id);
   if (!render_process_host)
     return;
   render_process_host->Send(own_message.release());
 }
 
@@ skipping 31 matching lines @@
       content::RenderProcessHost::FromID(launcher_child_id);
   // Guests inside <webview> do not support cross-process navigation and so we
   // do not allow guests to prerender content.
   if (rph && rph->IsGuest())
     return;
 
   LinkPrerender
       prerender(launcher_child_id, prerender_id, url, rel_types, referrer, size,
                 render_view_route_id, manager_->GetCurrentTimeTicks());
   prerenders_.push_back(prerender);
+  RecordLinkManagerAdded(rel_types);
   StartPrerenders();
 }
 
 void PrerenderLinkManager::OnCancelPrerender(int child_id, int prerender_id) {
   LinkPrerender* prerender = FindByLauncherChildIdAndPrerenderId(child_id,
                                                                  prerender_id);
   if (!prerender)
     return;
 
   CancelPrerender(prerender);
@@ skipping 168 matching lines @@
       prerenders_.erase(*i);
       continue;
     }
 
     // We have successfully started a new prerender.
     (*i)->handle = handle;
     ++total_started_prerender_count;
     handle->SetObserver(this);
     if (handle->IsPrerendering())
       OnPrerenderStart(handle);
+    RecordLinkManagerStarting((*i)->rel_types);
 
     running_launcher_and_render_view_routes.insert(
         launcher_and_render_view_route);
   }
 }
 
 PrerenderLinkManager::LinkPrerender*
 PrerenderLinkManager::FindByLauncherChildIdAndPrerenderId(int launcher_child_id,
                                                           int prerender_id) {
   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
@@ skipping 96 matching lines @@
   DCHECK(!prerender->is_match_complete_replacement);
   prerender->is_match_complete_replacement = true;
   Send(prerender->launcher_child_id,
        new PrerenderMsg_OnPrerenderStop(prerender->prerender_id));
   // Do not call RemovePrerender here. The replacement needs to stay connected
   // to the HTMLLinkElement in the renderer so it notices renderer-triggered
   // cancelations.
 }
 
 }  // namespace prerender