Add a new field trial for Instant.

chrome/browser/instant/instant_field_trial.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_INSTANT_INSTANT_FIELD_TRIAL_H_
 #define CHROME_BROWSER_INSTANT_INSTANT_FIELD_TRIAL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 10 matching lines @@
 // The following mutually exclusive groups each select a small random sample of
 // the remaining users. Instant is enabled with preloading for the EXPERIMENT
 // groups. It remains disabled, as is default, for the CONTROL groups.
 //
 // INSTANT_EXPERIMENT: Queries are issued as the user types, and previews are
 //     shown. If the user hasn't opted to send metrics (UMA) data, they are
 //     bounced back to INACTIVE.
 //
 // HIDDEN_EXPERIMENT: Queries are issued as the user types, but no preview is
 //     shown until they press <Enter>. If the user hasn't opted to send metrics
-//     (UMA) data, they are bounced back to INACTIVE.
+//     (UMA) data, they are bounced back to INACTIVE. Suggestions obtained from
+//     Instant are not propagated back to the omnibox.
 //
 // SILENT_EXPERIMENT: No queries are issued until the user presses <Enter>. No
 //     previews are shown. The user is not required to send metrics (UMA) data.
 //
+// SUGGEST_EXPERIMENT: Same as HIDDEN, except that the Instant suggestions are
+//     autocompleted inline into the omnibox.
+//
 // UMA_CONTROL: Instant is disabled. If the user hasn't opted to send metrics
 //     (UMA) data, they are bounced back to INACTIVE.
 //
 // ALL_CONTROL: Instant is disabled. The user is not required to send metrics
 //     (UMA) data.
 //
 // Users not chosen into any of the above groups are INACTIVE.
 //
 // Each non-INACTIVE group is split into two equal subgroups, to detect bias
 // between them when analyzing metrics. The subgroups are denoted by "_A" and
 // "_B" suffixes, and are treated identically for all other purposes.
 class InstantFieldTrial {
  public:
   enum Group {
     INACTIVE,
 
     INSTANT_EXPERIMENT_A,
     INSTANT_EXPERIMENT_B,
+
     HIDDEN_EXPERIMENT_A,
     HIDDEN_EXPERIMENT_B,
+
     SILENT_EXPERIMENT_A,
     SILENT_EXPERIMENT_B,
 
+    SUGGEST_EXPERIMENT_A,
+    SUGGEST_EXPERIMENT_B,
+
     UMA_CONTROL_A,
     UMA_CONTROL_B,
+
     ALL_CONTROL_A,
     ALL_CONTROL_B,
   };
 
   // Activate the field trial. Before this call, all calls to GetGroup will
   // return INACTIVE. *** MUST NOT BE CALLED MORE THAN ONCE. ***
   static void Activate();
 
   // Return the field trial group this profile belongs to.
   static Group GetGroup(Profile* profile);
 
   // Check if the user is in any of the EXPERIMENT groups.
   static bool IsInstantExperiment(Profile* profile);
 
-  // Check if the user is in the HIDDEN or SILENT EXPERIMENT groups.
+  // Check if the user is in the HIDDEN, SILENT or SUGGEST EXPERIMENT groups.
   static bool IsHiddenExperiment(Profile* profile);
 
   // Check if the user is in the SILENT EXPERIMENT group.
   static bool IsSilentExperiment(Profile* profile);
 
   // Returns a string describing the user's group. Can be added to histogram
   // names, to split histograms by field trial groups.
   static std::string GetGroupName(Profile* profile);
 
  // Returns a string denoting the user's group, for adding as a URL param.
  static std::string GetGroupAsUrlParam(Profile* profile);
 
+ // Returns whether the Instant suggested text should be autocompleted inline
+ // into the omnibox.
+ static bool ShouldSetSuggestedText(Profile* profile);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(InstantFieldTrial);
 };
 
 #endif  // CHROME_BROWSER_INSTANT_INSTANT_FIELD_TRIAL_H_