Create trial setup for PersistentOriginTrials

Adding 'OriginTrials' to the list of expected keyed services for Chrome.

For the url_loader_throttles.cc change, I realised that while all the
platforms in the trial list do return a valid pointer when the feature
flag is enabled, this is not necessarily true for other platforms.
In particular content/public/test/test_browser_context.cc does not
return a valid pointer unless explicitly instantiated, which caused
test failures on the test runners.

Bug: 1257579
Change-Id: Ie94020b6ef02df2f3fa0e159af2cc452b386b3c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4027571
Auto-Submit: Peter Pakkenberg <pbirk@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1075092}

content/browser/loader/url_loader_throttles.cc

@@ -76,9 +76,9 @@ CreateContentBrowserURLLoaderThrottles(
     }
   }
 
-  if (base::FeatureList::IsEnabled(features::kPersistentOriginTrials)) {
-    OriginTrialsControllerDelegate* origin_trials_delegate =
-        browser_context->GetOriginTrialsControllerDelegate();
+  OriginTrialsControllerDelegate* origin_trials_delegate =
+      browser_context->GetOriginTrialsControllerDelegate();
+  if (origin_trials_delegate) {
     // Critical Origin Trials may restart the network request, so only allow on
     // safe methods, since the origin trials in question may change request
     // headers or other aspects of the network request. We want to avoid servers

content/public/test/test_browser_context.h

@@ -88,7 +88,7 @@ class TestBrowserContext : public BrowserContext {
   std::unique_ptr<MockReduceAcceptLanguageControllerDelegate>
       reduce_accept_language_controller_delegate_;
   base::raw_ptr<OriginTrialsControllerDelegate>
-      origin_trials_controller_delegate_;
+      origin_trials_controller_delegate_ = nullptr;
   bool is_off_the_record_ = false;
 };
 

content/web_test/browser/web_test_origin_trial_throttle.cc

@@ -54,8 +54,10 @@ void WebTestOriginTrialThrottle::SetHeaderForRequest() {
   }
   std::string header_value = base::JoinString(
       base::span<std::string>(trials.begin(), trials.end()), ", ");
-  navigation_handle()->SetRequestHeader(kWebTestOriginTrialHeaderName,
-                                        header_value);
+  if (!header_value.empty()) {
+    navigation_handle()->SetRequestHeader(kWebTestOriginTrialHeaderName,
+                                          header_value);
+  }
 }
 
 const char* WebTestOriginTrialThrottle::GetNameForLogging() {

testing/variations/fieldtrial_testing_config.json

@@ -8537,6 +8537,25 @@
             ]
         }
     ],
+    "PersistentOriginTrials": [
+        {
+            "platforms": [
+                "android",
+                "android_webview",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "PersistentOriginTrials"
+                    ]
+                }
+            ]
+        }
+    ],
     "PreconnectInNetworkService": [
         {
             "platforms": [

third_party/blink/web_tests/VirtualTestSuites

@@ -1668,12 +1668,5 @@
     ],
     "args": ["--enable-features=SplitUserMediaQueues"],
     "expires": "Jul 1, 2023"
-  },
-  {
-    "prefix": "enable-persistent-origin-trials",
-    "platforms": ["Linux", "Mac", "Win"],
-    "bases": [ "http/tests/persistent-origin-trials/" ],
-    "args": ["--enable-features=PersistentOriginTrials"],
-    "expires": "Jul 1, 2023"
   }
 ]