Omnibox: Create DemoteByType Experiment

This experiment, which runs as part of the bundled omnibox field trial,
uses the field trial parameters to demote results of particular types
(e.g., HISTORY_TITLE results), possibly depending on context (e.g.,
search results page doing search term replacement).

It also improves the testing framework for field trial parameters,
allowing them to be cleared between consecutive TEST_F()s.

Tested via unit tests and by setting up my local variations server with
some parameters and making sure results can be demoted or
omitted.

BUG=264066

Review URL: https://chromiumcodereview.appspot.com/22031002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@216633 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 81 insertions, 1 deletions

diff --git a/chrome/browser/autocomplete/autocomplete_result_unittest.cc b/chrome/browser/autocomplete/autocomplete_result_unittest.cc
index 3038c27..d669f60 100644
--- a/chrome/browser/autocomplete/autocomplete_result_unittest.cc
+++ b/chrome/browser/autocomplete/autocomplete_result_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/autocomplete/autocomplete_result.h"
 
+#include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ -13,6 +14,9 @@
 #include "chrome/browser/search_engines/template_url_prepopulate_data.h"
 #include "chrome/browser/search_engines/template_url_service.h"
 #include "chrome/browser/search_engines/template_url_service_test_util.h"
+#include "chrome/common/autocomplete_match_type.h"
+#include "chrome/common/metrics/entropy_provider.h"
+#include "chrome/common/metrics/variations/variations_util.h"
 #include "chrome/test/base/testing_profile.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -30,7 +34,14 @@ class AutocompleteResultTest : public testing::Test  {
     int relevance;
   };
 
-  AutocompleteResultTest() {}
+  AutocompleteResultTest() {
+    // Destroy the existing FieldTrialList before creating a new one to avoid
+    // a DCHECK.
+    field_trial_list_.reset();
+    field_trial_list_.reset(new base::FieldTrialList(
+        new metrics::SHA1EntropyProvider("foo")));
+    chrome_variations::testing::ClearAllVariationParams();
+  }
 
   virtual void SetUp() OVERRIDE {
 #if defined(OS_ANDROID)
@@ -69,6 +80,8 @@ class AutocompleteResultTest : public testing::Test  {
   TemplateURLServiceTestUtil test_util_;
 
  private:
+  scoped_ptr<base::FieldTrialList> field_trial_list_;
+
   DISALLOW_COPY_AND_ASSIGN(AutocompleteResultTest);
 };
 
@@ -148,6 +161,7 @@ TEST_F(AutocompleteResultTest, Swap) {
   // Swap with a single match.
   ACMatches matches;
   AutocompleteMatch match;
+  match.relevance = 1;
   AutocompleteInput input(ASCIIToUTF16("a"), string16::npos, string16(), GURL(),
                           AutocompleteInput::INVALID_SPEC, false, false, false,
                           AutocompleteInput::ALL_MATCHES);
@@ -292,3 +306,69 @@ TEST_F(AutocompleteResultTest, SortAndCullDuplicateSearchURLs) {
             result.match_at(2)->destination_url.spec());
   EXPECT_EQ(900, result.match_at(2)->relevance);
 }
+
+TEST_F(AutocompleteResultTest, SortAndCullWithDemotionsByType) {
+  // Add some matches.
+  ACMatches matches;
+  {
+    AutocompleteMatch match;
+    match.destination_url = GURL("http://history-url/");
+    match.relevance = 1400;
+    match.type = AutocompleteMatchType::HISTORY_URL;
+    matches.push_back(match);
+  }
+  {
+    AutocompleteMatch match;
+    match.destination_url = GURL("http://search-what-you-typed/");
+    match.relevance = 1300;
+    match.type = AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED;
+    matches.push_back(match);
+  }
+  {
+    AutocompleteMatch match;
+    match.destination_url = GURL("http://history-title/");
+    match.relevance = 1200;
+    match.type = AutocompleteMatchType::HISTORY_TITLE;
+    matches.push_back(match);
+  }
+  {
+    AutocompleteMatch match;
+    match.destination_url = GURL("http://search-history/");
+    match.relevance = 500;
+    match.type = AutocompleteMatchType::SEARCH_HISTORY;
+    matches.push_back(match);
+  }
+
+  // Add a rule demoting history-url and killing history-title.
+  // Must be the same as kBundledExperimentFieldTrialName
+  // defined in omnibox_field_trial.cc.
+  const std::string kTrialName = "OmniboxBundledExperimentV1";
+  // Must be the same as kDemoteByTypeRule defined in
+  // omnibox_field_trial.cc.
+  const std::string kRuleName = "DemoteByType";
+  {
+    std::map<std::string, std::string> params;
+    params[kRuleName + ":3"] = "1:50,7:100,2:0";  // 3 == HOMEPAGE
+    ASSERT_TRUE(chrome_variations::AssociateVariationParams(
+        kTrialName, "A", params));
+  }
+  base::FieldTrialList::CreateFieldTrial(kTrialName, "A");
+
+  AutocompleteResult result;
+  result.AppendMatches(matches);
+  AutocompleteInput input(string16(), string16::npos, string16(), GURL(),
+                          AutocompleteInput::HOMEPAGE, false, false, false,
+                          AutocompleteInput::ALL_MATCHES);
+  result.SortAndCull(input, test_util_.profile());
+
+  // Check the new ordering.  The history-title results should be omitted.
+  // We cannot check relevance scores because the matches are sorted by
+  // demoted relevance but the actual relevance scores are not modified.
+  ASSERT_EQ(3u, result.size());
+  EXPECT_EQ("http://search-what-you-typed/",
+            result.match_at(0)->destination_url.spec());
+  EXPECT_EQ("http://history-url/",
+            result.match_at(1)->destination_url.spec());
+  EXPECT_EQ("http://search-history/",
+            result.match_at(2)->destination_url.spec());
+}