Adds InstantExtendedEnabledParam to the search request URL iff the query extraction flag is enabled.

chrome/browser/search/search.cc

 // Copyright 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/search/search.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
@@ skipping 344 matching lines @@
 uint64 EmbeddedSearchPageVersion() {
   FieldTrialFlags flags;
   if (GetFieldTrialInfo(&flags)) {
     return GetUInt64ValueForFlagWithDefault(kEmbeddedPageVersionFlagName,
                                             kEmbeddedPageVersionDefault,
                                             flags);
   }
   return kEmbeddedPageVersionDefault;
 }
 
+std::string InstantExtendedEnabledParam(bool for_search) {
+  if (for_search && !chrome::IsQueryExtractionEnabled())
+    return std::string();
+
+  uint64 instant_extended_api_version = EmbeddedSearchPageVersion();
+  if (instant_extended_api_version) {

[samarth, 2014/02/07 00:25:31]

Hmm I was going to say this should explicitly check version !=
kEmbeddedPageVersionDisabled but that no longer exists. So you don't need this
check after all :)

[kmadhusu, 2014/02/07 00:44:05]

True. Current version of EmbeddedSearchPageVersion() doesn't return
kEmbeddedPageVersionDisabled but it's better to have this check here to handle
"espv:0" field trials flag.

[samarth, 2014/02/07 17:50:00]

espv:0 is explicitly not a supported config anymore.

[kmadhusu, 2014/02/07 21:25:39]

Removed the check.

+    return std::string(google_util::kInstantExtendedAPIParam) + "=" +
+        base::Uint64ToString(instant_extended_api_version) + "&";
+  }
+  return std::string();
+}
+
 bool IsQueryExtractionEnabled() {
 #if defined(OS_IOS) || defined(OS_ANDROID)
   return true;
 #else
   if (!IsInstantExtendedAPIEnabled())
     return false;
 
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kEnableQueryExtraction))
     return true;
@@ skipping 401 matching lines @@
 
 // Given a FieldTrialFlags object, returns the boolean value of the provided
 // flag.
 bool GetBoolValueForFlagWithDefault(const std::string& flag,
                                     bool default_value,
                                     const FieldTrialFlags& flags) {
   return !!GetUInt64ValueForFlagWithDefault(flag, default_value ? 1 : 0, flags);
 }
 
 }  // namespace chrome