Add Field Trial for Prerender From Omnibox.

BUG=95066
TEST=None


Review URL: http://codereview.chromium.org/7825009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@101963 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 87 insertions, 18 deletions

diff --git a/chrome/browser/autocomplete/autocomplete_edit.cc b/chrome/browser/autocomplete/autocomplete_edit.cc
index 8c4958e..9777b41 100644
--- a/chrome/browser/autocomplete/autocomplete_edit.cc
+++ b/chrome/browser/autocomplete/autocomplete_edit.cc
@@ -7,7 +7,6 @@
 #include <string>
 
 #include "base/basictypes.h"
-#include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
@@ -24,6 +23,7 @@
 #include "chrome/browser/instant/instant_controller.h"
 #include "chrome/browser/net/predictor.h"
 #include "chrome/browser/net/url_fixer_upper.h"
+#include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/template_url.h"
@@ -208,6 +208,7 @@ bool AutocompleteEditModel::AcceptCurrentInstantPreview() {
 
 void AutocompleteEditModel::OnChanged() {
   const AutocompleteMatch current_match = CurrentMatch();
+
   string16 suggested_text;
 
   // Confer with the NetworkActionPredictor to determine what action, if any,
@@ -220,10 +221,8 @@ void AutocompleteEditModel::OnChanged() {
   bool might_support_instant = false;
   if (!DoInstant(current_match, &suggested_text, &might_support_instant)) {
     // Ignore the recommended action if Omnibox prerendering is not enabled.
-    if (!CommandLine::ForCurrentProcess()->HasSwitch(
-        switches::kPrerenderFromOmnibox)) {
+    if (!prerender::IsOmniboxEnabled(profile_))
       recommended_action = NetworkActionPredictor::ACTION_NONE;
-    }
 
     switch (recommended_action) {
       case NetworkActionPredictor::ACTION_PRERENDER:
@@ -835,10 +834,8 @@ void AutocompleteEditModel::OnResultChanged(bool default_match_changed) {
             match->fill_into_edit.substr(match->inline_autocomplete_offset);
       }
 
-      if (!CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kPrerenderFromOmnibox)) {
+      if (!prerender::IsOmniboxEnabled(profile_))
         DoPreconnect(*match);
-      }
 
       // We could prefetch the alternate nav URL, if any, but because there
       // can be many of these as a user types an initial series of characters,
diff --git a/chrome/browser/metrics/metrics_service.h b/chrome/browser/metrics/metrics_service.h
index 46867ed..7d9f0284 100644
--- a/chrome/browser/metrics/metrics_service.h
+++ b/chrome/browser/metrics/metrics_service.h
@@ -32,6 +32,7 @@ class HistogramSynchronizer;
 class MetricsLogBase;
 class MetricsReportingScheduler;
 class PrefService;
+class Profile;
 class TemplateURLService;
 
 namespace base {
@@ -39,10 +40,15 @@ class DictionaryValue;
 class ListValue;
 }
 
+namespace prerender {
+bool IsOmniboxEnabled(Profile* profile);
+}
+
 namespace webkit {
 struct WebPluginInfo;
 }
 
+
 class MetricsService : public NotificationObserver,
                        public URLFetcher::Delegate,
                        public MetricsServiceBase {
@@ -456,6 +462,7 @@ class MetricsService : public NotificationObserver,
 class MetricsServiceHelper {
  private:
   friend class InstantFieldTrial;
+  friend bool prerender::IsOmniboxEnabled(Profile* profile);
 
   // Returns true if prefs::kMetricsReportingEnabled is set.
   static bool IsMetricsReportingEnabled();
diff --git a/chrome/browser/prerender/prerender_field_trial.cc b/chrome/browser/prerender/prerender_field_trial.cc
index 9153eba..ba7184f 100644
--- a/chrome/browser/prerender/prerender_field_trial.cc
+++ b/chrome/browser/prerender/prerender_field_trial.cc
@@ -8,13 +8,19 @@
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
-#include "content/browser/renderer_host/resource_dispatcher_host.h"
+#include "chrome/browser/metrics/metrics_service.h"
+#include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
-
+#include "content/browser/renderer_host/resource_dispatcher_host.h"
 
 namespace prerender {
 
+// If the command line contains the --prerender-from-omnibox switch, enable
+// prerendering from the Omnibox. If not, enter the user into a field trial.
+void ConfigurePrerenderFromOmnibox();
+
 void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
   enum PrerenderOption {
     PRERENDER_OPTION_AUTO,
@@ -117,6 +123,46 @@ void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
   UMA_HISTOGRAM_ENUMERATION("Prerender.Sessions",
                             PrerenderManager::GetMode(),
                             PrerenderManager::PRERENDER_MODE_MAX);
+
+  ConfigurePrerenderFromOmnibox();
+}
+
+void ConfigurePrerenderFromOmnibox() {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kPrerenderFromOmnibox)) {
+    const base::FieldTrial::Probability kDivisor = 100;
+    const base::FieldTrial::Probability kEnabledProbability = 10;
+
+    scoped_refptr<base::FieldTrial> trial(
+        new base::FieldTrial("PrerenderFromOmnibox", kDivisor,
+                             "OmniboxPrerenderDisabled", 2012, 8, 30));
+
+    trial->AppendGroup("OmniboxPrerenderEnabled", kEnabledProbability);
+  }
+}
+
+bool IsOmniboxEnabled(Profile* profile) {
+  if (!profile || profile->IsOffTheRecord())
+    return false;
+
+  if (!PrerenderManager::IsPrerenderingPossible())
+    return false;
+
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kPrerenderFromOmnibox)) {
+    return true;
+  }
+
+  if (!MetricsServiceHelper::IsMetricsReportingEnabled())
+    return false;
+
+  const int group = base::FieldTrialList::FindValue("PrerenderFromOmnibox");
+  if (group == base::FieldTrial::kNotFinalized ||
+      group == base::FieldTrial::kDefaultGroupNumber) {
+    return false;
+  }
+
+  return true;
 }
 
 }  // namespace prerender
diff --git a/chrome/browser/prerender/prerender_field_trial.h b/chrome/browser/prerender/prerender_field_trial.h
index b7543ae6..368a515 100644
--- a/chrome/browser/prerender/prerender_field_trial.h
+++ b/chrome/browser/prerender/prerender_field_trial.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_PRERENDER_PRERENDER_FIELD_TRIAL_H_
 
 class CommandLine;
+class Profile;
 
 namespace prerender {
 
@@ -14,6 +15,10 @@ namespace prerender {
 // is assigned to a field trial.
 void ConfigurePrefetchAndPrerender(const CommandLine& command_line);
 
+// Returns true if the user has opted in or has been opted in to the
+// prerendering from Omnibox experiment.
+bool IsOmniboxEnabled(Profile* profile);
+
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_FIELD_TRIAL_H_
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index 4e73530..61a8867 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -6,7 +6,6 @@
 
 #include <string>
 
-#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/time.h"
@@ -17,6 +16,7 @@
 #include "chrome/browser/history/top_sites.h"
 #include "chrome/browser/prerender/prerender_condition.h"
 #include "chrome/browser/prerender/prerender_contents.h"
+#include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
 #include "chrome/browser/prerender/prerender_histograms.h"
 #include "chrome/browser/prerender/prerender_history.h"
@@ -269,8 +269,7 @@ bool PrerenderManager::AddPrerenderFromLinkRelPrerender(int process_id,
 }
 
 bool PrerenderManager::AddPrerenderFromOmnibox(const GURL& url) {
-  CommandLine* cl = CommandLine::ForCurrentProcess();
-  if (!cl->HasSwitch(switches::kPrerenderFromOmnibox))
+  if (!IsOmniboxEnabled(profile_))
     return false;
 
   return AddPrerender(ORIGIN_OMNIBOX, std::make_pair(-1, -1), url, GURL());
@@ -952,12 +951,13 @@ void PrerenderManager::ScheduleDeleteOldTabContents(
   }
 }
 
-Value* PrerenderManager::GetAsValue() const {
+DictionaryValue* PrerenderManager::GetAsValue() const {
   DCHECK(CalledOnValidThread());
   DictionaryValue* dict_value = new DictionaryValue();
   dict_value->Set("history", prerender_history_->GetEntriesAsValue());
   dict_value->Set("active", GetActivePrerendersAsValue());
   dict_value->SetBoolean("enabled", enabled_);
+  dict_value->SetBoolean("omnibox_enabled", IsOmniboxEnabled(profile_));
   // If prerender is disabled via a flag this method is not even called.
   if (IsControlGroup())
     dict_value->SetString("disabled_reason", "(Disabled for testing)");
diff --git a/chrome/browser/prerender/prerender_manager.h b/chrome/browser/prerender/prerender_manager.h
index 7e157a71..acdf410 100644
--- a/chrome/browser/prerender/prerender_manager.h
+++ b/chrome/browser/prerender/prerender_manager.h
@@ -28,6 +28,10 @@
 class Profile;
 class TabContents;
 
+namespace base {
+class DictionaryValue;
+}
+
 #if defined(COMPILER_GCC)
 
 namespace __gnu_cxx {
@@ -176,7 +180,7 @@ class PrerenderManager : public base::SupportsWeakPtr<PrerenderManager>,
   // Returns a Value object containing the active pages being prerendered, and
   // a history of pages which were prerendered. The caller is responsible for
   // deleting the return value.
-  base::Value* GetAsValue() const;
+  base::DictionaryValue* GetAsValue() const;
 
   // Clears the data indicated by which bits of clear_flags are set.
   //
diff --git a/chrome/browser/resources/net_internals/prerender_view.html b/chrome/browser/resources/net_internals/prerender_view.html
index 2b663da..3296ed5 100644
--- a/chrome/browser/resources/net_internals/prerender_view.html
+++ b/chrome/browser/resources/net_internals/prerender_view.html
@@ -2,6 +2,8 @@
   <h4>Prerender</h4>
   <ul>
     <li>Prerender Enabled: <span id=prerender-view-enabled-span></span></li>
+    <li>Prerender Omnibox Enabled: 
+        <span id=prerender-view-omnibox-enabled-span></span></li>
   </ul>
   <p>
     Active Prerender Pages
diff --git a/chrome/browser/resources/net_internals/prerender_view.js b/chrome/browser/resources/net_internals/prerender_view.js
index 33ab3a8..746306b 100644
--- a/chrome/browser/resources/net_internals/prerender_view.js
+++ b/chrome/browser/resources/net_internals/prerender_view.js
@@ -11,6 +11,7 @@ var PrerenderView = (function() {
   // IDs for special HTML elements in prerender_view.html
   var MAIN_BOX_ID = 'prerender-view-tab-content';
   var ENABLED_SPAN_ID = 'prerender-view-enabled-span';
+  var OMNIBOX_ENABLED_SPAN_ID = 'prerender-view-omnibox-enabled-span';
   var HISTORY_DIV_ID = 'prerender-view-history-div';
   var ACTIVE_DIV_ID = 'prerender-view-active-div';
 
@@ -28,6 +29,7 @@ var PrerenderView = (function() {
 
     g_browser.addPrerenderInfoObserver(this);
     this.prerenderEnabledSpan_ = $(ENABLED_SPAN_ID);
+    this.prerenderOmniboxEnabledSpan_ = $(OMNIBOX_ENABLED_SPAN_ID);
     this.prerenderHistoryDiv_ = $(HISTORY_DIV_ID);
     this.prerenderActiveDiv_ = $(ACTIVE_DIV_ID);
   }
@@ -47,6 +49,7 @@ var PrerenderView = (function() {
 
     onPrerenderInfoChanged: function(prerenderInfo) {
       this.prerenderEnabledSpan_.textContent = '';
+      this.prerenderOmniboxEnabledSpan_.textContent = '';
       this.prerenderHistoryDiv_.innerHTML = '';
       this.prerenderActiveDiv_.innerHTML = '';
 
@@ -59,6 +62,11 @@ var PrerenderView = (function() {
         }
       }
 
+      if (prerenderInfo && ('omnibox_enabled' in prerenderInfo)) {
+        this.prerenderOmniboxEnabledSpan_.textContent =
+            prerenderInfo.omnibox_enabled.toString();
+      }
+
       if (!isValidPrerenderInfo(prerenderInfo))
         return false;
 
diff --git a/chrome/browser/ui/webui/net_internals_ui.cc b/chrome/browser/ui/webui/net_internals_ui.cc
index 8dd9a59..a75ff83 100644
--- a/chrome/browser/ui/webui/net_internals_ui.cc
+++ b/chrome/browser/ui/webui/net_internals_ui.cc
@@ -640,12 +640,12 @@ void NetInternalsMessageHandler::OnEnableHttpThrottling(const ListValue* list) {
 void NetInternalsMessageHandler::OnGetPrerenderInfo(const ListValue* list) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  Value* value = NULL;
+  DictionaryValue* value = NULL;
   prerender::PrerenderManager* prerender_manager = prerender_manager_.get();
   if (!prerender_manager) {
-    DictionaryValue* dict_value = new DictionaryValue();
-    dict_value->SetBoolean("enabled", false);
-    value = dict_value;
+    value = new DictionaryValue();
+    value->SetBoolean("enabled", false);
+    value->SetBoolean("omnibox_enabled", false);
   } else {
     value = prerender_manager->GetAsValue();
   }