[SEC] Implement attribution parameter for Play API search engine

BUG=1002271
R=pkasting@chromium.org

Change-Id: I51d8b4b41bfab30271edb3d67ebada490da0535f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1848617
Commit-Queue: Pavel Yatsuk <pavely@chromium.org>
Reviewed-by: Kevin Bailey <krb@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704323}

components/search_engines/template_url.cc

@@ -386,6 +386,11 @@ std::string TemplateURLRef::ReplaceSearchTerms(
     query_params.push_back(search_terms_args.additional_query_params);
   if (!gurl.query().empty())
     query_params.push_back(gurl.query());
+  if (owner_->created_from_play_api()) {
+    // Append attribution parameter to query originating from Play API search
+    // engine.
+    query_params.push_back("chrome_dse_attribution=1");
+  }
 
   if (query_params.empty())
     return url;

components/search_engines/template_url_unittest.cc

@@ -802,6 +802,33 @@ TEST_F(TemplateURLTest, ReplaceCurrentPageUrl) {
   }
 }
 
+// Tests appending attribution parameter to queries originating from Play API
+// search engine.
+TEST_F(TemplateURLTest, PlayAPIAttribution) {
+  const struct TestData {
+    const char* url;
+    base::string16 terms;
+    bool created_from_play_api;
+    const char* output;
+  } test_data[] = {{"http://foo/?q={searchTerms}", ASCIIToUTF16("bar"), false,
+                    "http://foo/?q=bar"},
+                   {"http://foo/?q={searchTerms}", ASCIIToUTF16("bar"), true,
+                    "http://foo/?q=bar&chrome_dse_attribution=1"}};
+  TemplateURLData data;
+  for (size_t i = 0; i < base::size(test_data); ++i) {
+    data.SetURL(test_data[i].url);
+    data.created_from_play_api = test_data[i].created_from_play_api;
+    TemplateURL url(data);
+    EXPECT_TRUE(url.url_ref().IsValid(search_terms_data_));
+    ASSERT_TRUE(url.url_ref().SupportsReplacement(search_terms_data_));
+    GURL result(url.url_ref().ReplaceSearchTerms(
+        TemplateURLRef::SearchTermsArgs(test_data[i].terms),
+        search_terms_data_));
+    ASSERT_TRUE(result.is_valid());
+    EXPECT_EQ(test_data[i].output, result.spec());
+  }
+}
+
 TEST_F(TemplateURLTest, Suggestions) {
   struct TestData {
     const int accepted_suggestion;