[Zine|Feed] Update default referrer URL

Changes the referrer value to:
* https://www.googleapis.com/auth/chrome-content-suggestions for
  NTP Article Suggestions

Bug: 903013
Change-Id: I62460e45d6134058d49c220c580e8a2f7834365d
Reviewed-on: https://chromium-review.googlesource.com/c/1325214Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611126}

chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsConfig.java

@@ -39,7 +39,7 @@ public final class SuggestionsConfig {
      * It must be kept in sync with //components/ntp_suggestions/features.cc
      */
     private static final String DEFAULT_CONTENT_SUGGESTIONS_REFERRER_URL =
-            "https://discover.google.com/";
+            "https://www.googleapis.com/auth/chrome-content-suggestions";
 
     /** Default value of referrer URL for contextual suggestions. */
     private static final String DEFAULT_CONTEXTUAL_SUGGESTIONS_REFERRER_URL =

components/ntp_snippets/features.cc

@@ -160,7 +160,8 @@ std::vector<const base::Feature*> GetAllFeatures() {
 }
 
 // Default referrer for the content suggestions.
-const char kDefaultReferrerUrl[] = "https://discover.google.com/";
+const char kDefaultReferrerUrl[] =
+    "https://www.googleapis.com/auth/chrome-content-suggestions";
 
 // Provides ability to customize the referrer URL.
 // When specifying a referrer through a field trial, it must contain a path.

components/ntp_snippets/features_unittest.cc

@@ -14,29 +14,29 @@
 namespace ntp_snippets {
 
 namespace {
-const char kTestFeedURL[] = "https://test.google.com/";
+const char kExpectedZineURL[] =
+    "https://www.googleapis.com/auth/chrome-content-suggestions";
+const char kTestZineURL[] = "https://test.google.com/";
 }  // namespace
 
 TEST(FeaturesTest, GetContentSuggestionsReferrerURL_DefaultValue) {
   base::test::ScopedFeatureList feature_list;
   feature_list.InitAndEnableFeature(kArticleSuggestionsFeature);
-  EXPECT_EQ("https://discover.google.com/", GetContentSuggestionsReferrerURL());
+  EXPECT_EQ(kExpectedZineURL, GetContentSuggestionsReferrerURL());
 
   // In code this will be often used inside of a GURL.
-  EXPECT_EQ("https://discover.google.com/",
-            GURL(GetContentSuggestionsReferrerURL()));
-  EXPECT_EQ("https://discover.google.com/",
-            GURL(GetContentSuggestionsReferrerURL()).spec());
+  EXPECT_EQ(kExpectedZineURL, GURL(GetContentSuggestionsReferrerURL()));
+  EXPECT_EQ(kExpectedZineURL, GURL(GetContentSuggestionsReferrerURL()).spec());
 }
 
 TEST(FeaturesTest, GetContentSuggestionsReferrerURL_ParamValue) {
   base::test::ScopedFeatureList feature_list;
 
   std::map<std::string, std::string> parameters;
-  parameters["referrer_url"] = kTestFeedURL;
+  parameters["referrer_url"] = kTestZineURL;
   feature_list.InitAndEnableFeatureWithParameters(kArticleSuggestionsFeature,
                                                   parameters);
-  EXPECT_EQ(kTestFeedURL, GetContentSuggestionsReferrerURL());
+  EXPECT_EQ(kTestZineURL, GetContentSuggestionsReferrerURL());
 }
 
 }  // namespace ntp_snippets