[floc] For the OT, set allows_third_party and make it finch controllable

We expect doing 3rd-party OT for FLoC, thus setting
origin_trial_allows_third_party. Also, gate the OT by a base::Feature,
as this allows us to keep the experimentation under the global usage
limit.

Bug: 1163394
Change-Id: Ibaf9554397f8d46fa68c837fe58acc66676a2401
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2611953Reviewed-by: Yoav Weiss <yoavweiss@chromium.org>
Commit-Queue: Yao Xiao <yaoxia@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842729}

chrome/browser/federated_learning/floc_origin_trial_browsertest.cc

@@ -21,7 +21,10 @@ constexpr char kBaseDataDir[] = "chrome/test/data/federated_learning";
 
 class FlocOriginTrialBrowserTest : public InProcessBrowserTest {
  public:
-  FlocOriginTrialBrowserTest() = default;
+  FlocOriginTrialBrowserTest() {
+    scoped_feature_list_.InitAndEnableFeature(
+        blink::features::kInterestCohortAPIOriginTrial);
+  }
 
   void SetUpOnMainThread() override {
     InProcessBrowserTest::SetUpOnMainThread();
@@ -71,6 +74,9 @@ class FlocOriginTrialBrowserTest : public InProcessBrowserTest {
     return browser()->tab_strip_model()->GetActiveWebContents();
   }
 
+ protected:
+  base::test::ScopedFeatureList scoped_feature_list_;
+
  private:
   std::unique_ptr<content::URLLoaderInterceptor> url_loader_interceptor_;
 };
@@ -87,4 +93,23 @@ IN_PROC_BROWSER_TEST_F(FlocOriginTrialBrowserTest, OriginTrialDisabled) {
   EXPECT_FALSE(HasInterestCohortApi(web_contents()));
 }
 
+class FlocOriginTrialBrowserTestBaseFeatureDisabled
+    : public FlocOriginTrialBrowserTest {
+ public:
+  FlocOriginTrialBrowserTestBaseFeatureDisabled() {
+    scoped_feature_list_.Reset();
+    scoped_feature_list_.InitAndDisableFeature(
+        blink::features::kInterestCohortAPIOriginTrial);
+  }
+};
+
+IN_PROC_BROWSER_TEST_F(FlocOriginTrialBrowserTestBaseFeatureDisabled,
+                       OriginTrialEnabled) {
+  ui_test_utils::NavigateToURL(browser(), OriginTrialEnabledURL());
+
+  // If the base::Feature is disabled, the OT / API is disabled regardless of
+  // the OT config.
+  EXPECT_FALSE(HasInterestCohortApi(web_contents()));
+}
+
 }  // namespace federated_learning

third_party/blink/common/features.cc

@@ -859,5 +859,11 @@ const base::Feature kSendCnameAliasesToSubresourceFilterFromRenderer{
     "SendCnameAliasesToSubresourceFilterFromRenderer",
     base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Kill switch for the InterestCohort API origin trial, i.e. if disabled, the
+// API exposure will be disabled regardless of the OT config.
+// (See https://github.com/WICG/floc.)
+const base::Feature kInterestCohortAPIOriginTrial{
+    "InterestCohortAPIOriginTrial", base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace features
 }  // namespace blink

third_party/blink/public/common/features.h

@@ -354,6 +354,8 @@ BLINK_COMMON_EXPORT extern const base::Feature kWebRtcDistinctWorkerThread;
 BLINK_COMMON_EXPORT extern const base::Feature
     kSendCnameAliasesToSubresourceFilterFromRenderer;
 
+BLINK_COMMON_EXPORT extern const base::Feature kInterestCohortAPIOriginTrial;
+
 }  // namespace features
 }  // namespace blink
 

third_party/blink/renderer/core/origin_trials/origin_trial_context.cc

@@ -384,7 +384,10 @@ bool OriginTrialContext::CanEnableTrialFromName(const StringView& trial_name) {
       !base::FeatureList::IsEnabled(network::features::kTrustTokens)) {
     return false;
   }
-
+  if (trial_name == "InterestCohortAPI" &&
+      !base::FeatureList::IsEnabled(features::kInterestCohortAPIOriginTrial)) {
+    return false;
+  }
   return true;
 }
 

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1035,6 +1035,7 @@
     {
       name: "InterestCohortAPI",
       origin_trial_feature_name: "InterestCohortAPI",
+      origin_trial_allows_third_party: true,
     },
     {
       name: "IntersectionObserverDocumentScrollingElementRoot",

third_party/blink/web_tests/VirtualTestSuites

@@ -768,6 +768,11 @@
     "bases": [ "http/tests/origin_trials/webexposed/bfcache-experiment-http-header-origin-trial.php" ],
     "args": [ "--enable-features=BackForwardCacheABExperimentControl" ]
   },
+  {
+    "prefix": "interest-cohort-api-origin-trial",
+    "bases": [ "http/tests/origin_trials/webexposed/interest-cohort-origin-trial-interfaces.html" ],
+    "args": [ "--enable-features=InterestCohortAPIOriginTrial" ]
+  },
   {
     "prefix": "threaded-composited-iframes",
     "bases": ["external/wpt/is-input-pending"],

third_party/blink/web_tests/http/tests/origin_trials/webexposed/interest-cohort-origin-trial-interfaces-expected.txt

+Test that the API exists with origin trial token
+
+FAILURE

third_party/blink/web_tests/http/tests/origin_trials/webexposed/interest-cohort-origin-trial-interfaces.html

@@ -5,14 +5,20 @@ generate_token.py http://127.0.0.1:8000 InterestCohortAPI --expire-timestamp=200
 -->
 <meta http-equiv="origin-trial" content="A1q7Ss8yaDaFBy5/0JLZCpLDbCD0o4uPIJkE9YEkUUuOBdvmdJiBcoNSy9OvLuRh+XsWnW3zP+0UcWI2T1vP1AwAAABZeyJvcmlnaW4iOiAiaHR0cDovLzEyNy4wLjAuMTo4MDAwIiwgImZlYXR1cmUiOiAiSW50ZXJlc3RDb2hvcnRBUEkiLCAiZXhwaXJ5IjogMjAwMDAwMDAwMH0=" />
 <title>Interest Cohort API - interfaces exposed by origin trial</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="/resources/origin-trials-helper.js"></script>
+<body>
+<p>Test that the API exists with origin trial token</p>
+<div id="result"></div>
 <script>
 'use strict'
 
-test(t => {
-  assert_true(document.interestCohort instanceof Function, 'interestCohort function can be accessed on document');
-}, 'Interest Cohort API entry point in Origin-Trial enabled document.');
+if (window.testRunner) {
+  testRunner.dumpAsText();
+}
 
+if (document.interestCohort instanceof Function) {
+  document.getElementById("result").innerHTML += "SUCCESS";
+} else {
+  document.getElementById("result").innerHTML += "FAILURE";
+}
 </script>
+</body>

third_party/blink/web_tests/virtual/interest-cohort-api-origin-trial/README.md

+*This suite runs the tests with**
+`--enable-features=InterestCohortAPIOriginTrial`

third_party/blink/web_tests/virtual/interest-cohort-api-origin-trial/http/tests/origin_trials/webexposed/interest-cohort-origin-trial-interfaces-expected.txt

+Test that the API exists with origin trial token
+
+SUCCESS