Change how Prerender control group works so the "matched" case is recorded.

This changes the control group to do a prefetch, but no prerender. It also fixes a number
of issues which get exposed when that is the behavior.

BUG=None
TEST=Get selected in control group, search for prerendered page, make sure it makes sense.

Review URL: http://codereview.chromium.org/6720021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@80345 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 13 insertions, 2 deletions

diff --git a/chrome/browser/prerender/prerender_contents.cc b/chrome/browser/prerender/prerender_contents.cc
index 72ed1a2..166f4f9 100644
--- a/chrome/browser/prerender/prerender_contents.cc
+++ b/chrome/browser/prerender/prerender_contents.cc
@@ -490,6 +490,9 @@ void PrerenderContents::RendererUnresponsive(RenderViewHost* render_view_host,
 
 base::ProcessMetrics* PrerenderContents::MaybeGetProcessMetrics() {
   if (process_metrics_.get() == NULL) {
+    // If a PrenderContents hasn't started prerending, don't be fully formed.
+    if (!render_view_host_ || !render_view_host_->process())
+      return NULL;
     base::ProcessHandle handle = render_view_host_->process()->GetHandle();
     if (handle == base::kNullProcessHandle)
       return NULL;
diff --git a/chrome/browser/prerender/prerender_field_trial.cc b/chrome/browser/prerender/prerender_field_trial.cc
index d15a173..615d258 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -96,7 +96,7 @@ void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
             PrerenderManager::PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP);
       } else if (trial_group == kPrerenderControl1Group ||
                  trial_group == kPrerenderControl2Group) {
-        ResourceDispatcherHost::set_is_prefetch_enabled(false);
+        ResourceDispatcherHost::set_is_prefetch_enabled(true);
         PrerenderManager::SetMode(
             PrerenderManager::PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP);
       } else {
diff --git a/chrome/browser/prerender/prerender_final_status.cc b/chrome/browser/prerender/prerender_final_status.cc
index 52dcdad..cfad313 100644
--- a/chrome/browser/prerender/prerender_final_status.cc
+++ b/chrome/browser/prerender/prerender_final_status.cc
@@ -10,6 +10,11 @@ namespace prerender {
 
 void RecordFinalStatus(FinalStatus final_status) {
   DCHECK(final_status != FINAL_STATUS_MAX);
+  // FINAL_STATUS_CONTROL_GROUP indicates that the PrerenderContents
+  // was created only to measure "would-have-been-prerendered" for
+  // control group measurements. Don't pollute data with it.
+  if (final_status == FINAL_STATUS_CONTROL_GROUP)
+    return;
   UMA_HISTOGRAM_ENUMERATION("Prerender.FinalStatus",
                             final_status,
                             FINAL_STATUS_MAX);
diff --git a/chrome/browser/prerender/prerender_final_status.h b/chrome/browser/prerender/prerender_final_status.h
index a0ec142..48122be 100644
--- a/chrome/browser/prerender/prerender_final_status.h
+++ b/chrome/browser/prerender/prerender_final_status.h
@@ -28,6 +28,7 @@ enum FinalStatus {
   FINAL_STATUS_TOO_MANY_PROCESSES,
   FINAL_STATUS_RATE_LIMIT_EXCEEDED,
   FINAL_STATUS_PENDING_SKIPPED,
+  FINAL_STATUS_CONTROL_GROUP,
   FINAL_STATUS_MAX,
 };
 
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index d468ea0..49335a3 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -180,7 +180,9 @@ bool PrerenderManager::AddPreload(const GURL& url,
                              GetCurrentTime());
 
   prerender_list_.push_back(data);
-  if (!IsControlGroup()) {
+  if (IsControlGroup()) {
+    data.contents_->set_final_status(FINAL_STATUS_CONTROL_GROUP);
+  } else {
     last_prerender_start_time_ = GetCurrentTimeTicks();
     data.contents_->StartPrerendering();
   }