Adds a field trial flag to control whether to use an alternate Instant search base page URL for pre…

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 56 matching lines @@
 const char kHideVerbatimFlagName[] = "hide_verbatim";
 const char kPrefetchSearchResultsFlagName[] = "prefetch_results";
 const char kPrefetchSearchResultsOnSRP[] = "prefetch_results_srp";
 const char kPrerenderInstantUrlOnOmniboxFocus[] =
     "prerender_instant_url_on_omnibox_focus";
 
 // Controls whether to reuse prerendered Instant Search base page to commit any
 // search query.
 const char kReuseInstantSearchBasePage[] = "reuse_instant_search_base_page";
 
+// Controls whether to use the alternate Instant search base URL. This allows
+// experimentation of Instant search.
+const char kUseAltInstantURL[] = "use_alternate_instant_url";
+const char kAltInstantURLPath[] = "search";
+const char kAltInstantURLQueryParams[] = "&qbp=1";
+
 const char kDisplaySearchButtonFlagName[] = "display_search_button";
 const char kOriginChipFlagName[] = "origin_chip";
 #if !defined(OS_IOS) && !defined(OS_ANDROID)
 const char kEnableQueryExtractionFlagName[] = "query_extraction";
 #endif
 const char kShouldShowGoogleLocalNTPFlagName[] = "google_local_ntp";
 
 // Constants for the field trial name and group prefix.
 // Note in M30 and below this field trial was named "InstantExtended" and in
 // M31 was renamed to EmbeddedSearch for clarity and cleanliness.  Since we
@@ skipping 456 matching lines @@
       !google_util::StartsWithCommandLineGoogleBaseURL(instant_url)) {
     GURL::Replacements replacements;
     const std::string secure_scheme(url::kHttpsScheme);
     replacements.SetSchemeStr(secure_scheme);
     instant_url = instant_url.ReplaceComponents(replacements);
   }
 
   if (!IsURLAllowedForSupervisedUser(instant_url, profile))
     return GURL();
 
+  if (ShouldUseAltInstantURL()) {
+    GURL::Replacements replacements;
+    const std::string path(kAltInstantURLPath);
+    replacements.SetPathStr(path);
+    const std::string query(
+        instant_url.query() + std::string(kAltInstantURLQueryParams));
+    replacements.SetQueryStr(query);
+    instant_url = instant_url.ReplaceComponents(replacements);
+  }
   return instant_url;
 }
 
 // Returns URLs associated with the default search engine for |profile|.
 std::vector<GURL> GetSearchURLs(Profile* profile) {
   std::vector<GURL> result;
   TemplateURL* template_url = GetDefaultSearchProviderTemplateURL(profile);
   if (!template_url)
     return result;
   for (size_t i = 0; i < template_url->URLCount(); ++i) {
@@ skipping 264 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);
 }
 
+bool ShouldUseAltInstantURL() {

[samarth, 2014/06/20 04:43:23]

Put this in an anonymous namespace?

[kmadhusu, 2014/06/20 16:01:53]

If I put this in anonymous namespace, I will not be able to test this function
separately.

+  FieldTrialFlags flags;
+  return GetFieldTrialInfo(&flags) && GetBoolValueForFlagWithDefault(
+      kUseAltInstantURL, false, flags);
+}
+
 }  // namespace chrome