Enable referrer policy in policy container by default

The policy container is a project to unify and fix security policies
inheritance for local scheme documents. In the first prototype, we
added referrer policy to the policy container behind a flag. Since
this seems to be working well, let's enable the flag by default.

Bug: 1130587
Change-Id: I66bd8fd823b3c114ba7f3e671eb73902955219f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2573080
Commit-Queue: Antonio Sartori <antoniosartori@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835606}

third_party/blink/common/features.cc

@@ -686,7 +686,7 @@ const base::FeatureParam<int> kInstallingServiceWorkerOutstandingThrottledLimit{
 // the policy container. The policy container for the current document is
 // attached to the RenderFrameHost and mirrored to the LocalFrame in Blink.
 const base::Feature kPolicyContainer{"PolicyContainer",
-                                     base::FEATURE_DISABLED_BY_DEFAULT};
+                                     base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kInputPredictorTypeChoice{
     "InputPredictorTypeChoice", base::FEATURE_DISABLED_BY_DEFAULT};

third_party/blink/web_tests/VirtualTestSuites

@@ -723,7 +723,7 @@
     "prefix": "policy-container",
     "bases": [ "external/wpt/referrer-policy",
                "fast/dom/DOMImplementation" ],
-    "args": [ "--enable-features=PolicyContainer" ]
+    "args": [ "--disable-features=PolicyContainer" ]
   },
   {
     "prefix": "subresource-web-bundles-disabled",

third_party/blink/web_tests/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-about-blank-expected.txt

 This is a testharness.js-based test.
 PASS The fetch() API in an about:blank iframe with the 'client' referrer is fetched with no 'Referer' header
-FAIL The fetch() API in an about:blank iframe with a custom URL referrer is fetched with a 'Referer` header that uses the outer document's URL along with its referrer policy assert_equals: expected "http://web-platform.test:8001/" but got "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-about-blank.html/custom"
+PASS The fetch() API in an about:blank iframe with a custom URL referrer is fetched with a 'Referer` header that uses the outer document's URL along with its referrer policy
 FAIL The value of document.referrer in an about:blank iframe is the outer document's full URL, regardless of referrer policy assert_equals: expected "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-about-blank.html" but got "http://web-platform.test:8001/"
 PASS A subresource fetched from an about:blank iframe is fetched with no 'Referer' header
 Harness: the test ran to completion.

third_party/blink/web_tests/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-history-about-srcdoc-expected.txt

-This is a testharness.js-based test.
-FAIL History navigation reuses original policy. assert_equals: History navigation reuses original policy. expected (undefined) undefined but got (string) "http://web-platform.test:8001/custom"
-PASS New srcdoc iframe uses new policy.
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-javascript-child-expected.txt

 This is a testharness.js-based test.
-FAIL Referrer Policy: iframes with javascript url reuse referrer policy assert_equals: expected "http://web-platform.test:8001/custom" but got "http://web-platform.test:8001/"
-FAIL Referrer Policy: iframes with javascript url reuse referrer policy 1 assert_equals: expected (undefined) undefined but got (string) "http://web-platform.test:8001/"
+PASS Referrer Policy: iframes with javascript url reuse referrer policy
+PASS Referrer Policy: iframes with javascript url reuse referrer policy 1
 FAIL Referrer Policy: iframes with javascript url reuse referrer policy 2 assert_equals: expected (undefined) undefined but got (string) "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-javascript-child.html"
-FAIL Referrer Policy: iframes with javascript url reuse referrer policy 3 assert_equals: expected (undefined) undefined but got (string) "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-javascript-child.html"
+PASS Referrer Policy: iframes with javascript url reuse referrer policy 3
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-javascript-expected.txt

-This is a testharness.js-based test.
-PASS Referrer Policy: iframes with javascript url reuse referrer policy
-FAIL Referrer Policy: iframes with javascript url reuse referrer policy 1 assert_equals: expected "http://web-platform.test:8001/custom" but got "http://web-platform.test:8001/"
-Harness: the test ran to completion.
-

third_party/blink/web_tests/virtual/policy-container/README.md

-This directory is for testing Referrer Policy within the PolicyContainer.
+This directory is for testing Referrer Policy without the PolicyContainer.
 
-This test suite runs the tests with --enable-features=PolicyContainer. The
-experimental flag enables setting/inheriting Referrer Policy via the Policy
-Container, a new mechanism which uses policies stored in the browser on the
-RenderFrameHost as authoritative policies for creating new frames.
+This test suite runs the tests with --disable-features=PolicyContainer. The
+experimental flag to enable setting/inheriting Referrer Policy via the Policy
+Container has been turned on by default, but we keep the flag and this test for
+some time to ensure that we can switch back in case something should not work as
+expected.

third_party/blink/web_tests/virtual/policy-container/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-about-blank-expected.txt

 This is a testharness.js-based test.
 PASS The fetch() API in an about:blank iframe with the 'client' referrer is fetched with no 'Referer' header
-PASS The fetch() API in an about:blank iframe with a custom URL referrer is fetched with a 'Referer` header that uses the outer document's URL along with its referrer policy
+FAIL The fetch() API in an about:blank iframe with a custom URL referrer is fetched with a 'Referer` header that uses the outer document's URL along with its referrer policy assert_equals: expected "http://web-platform.test:8001/" but got "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-about-blank.html/custom"
 FAIL The value of document.referrer in an about:blank iframe is the outer document's full URL, regardless of referrer policy assert_equals: expected "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-about-blank.html" but got "http://web-platform.test:8001/"
 PASS A subresource fetched from an about:blank iframe is fetched with no 'Referer' header
 Harness: the test ran to completion.

third_party/blink/web_tests/virtual/policy-container/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-history-about-srcdoc-expected.txt

 This is a testharness.js-based test.
-PASS History navigation reuses original policy.
+FAIL History navigation reuses original policy. assert_equals: History navigation reuses original policy. expected (undefined) undefined but got (string) "http://web-platform.test:8001/custom"
 PASS New srcdoc iframe uses new policy.
 Harness: the test ran to completion.
 

third_party/blink/web_tests/virtual/policy-container/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-javascript-child-expected.txt

 This is a testharness.js-based test.
-PASS Referrer Policy: iframes with javascript url reuse referrer policy
-PASS Referrer Policy: iframes with javascript url reuse referrer policy 1
+FAIL Referrer Policy: iframes with javascript url reuse referrer policy assert_equals: expected "http://web-platform.test:8001/custom" but got "http://web-platform.test:8001/"
+FAIL Referrer Policy: iframes with javascript url reuse referrer policy 1 assert_equals: expected (undefined) undefined but got (string) "http://web-platform.test:8001/"
 FAIL Referrer Policy: iframes with javascript url reuse referrer policy 2 assert_equals: expected (undefined) undefined but got (string) "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-javascript-child.html"
-PASS Referrer Policy: iframes with javascript url reuse referrer policy 3
+FAIL Referrer Policy: iframes with javascript url reuse referrer policy 3 assert_equals: expected (undefined) undefined but got (string) "http://web-platform.test:8001/referrer-policy/generic/inheritance/iframe-inheritance-javascript-child.html"
 Harness: the test ran to completion.
 

third_party/blink/web_tests/virtual/policy-container/external/wpt/referrer-policy/generic/inheritance/iframe-inheritance-javascript-expected.txt

 This is a testharness.js-based test.
 PASS Referrer Policy: iframes with javascript url reuse referrer policy
-PASS Referrer Policy: iframes with javascript url reuse referrer policy 1
+FAIL Referrer Policy: iframes with javascript url reuse referrer policy 1 assert_equals: expected "http://web-platform.test:8001/custom" but got "http://web-platform.test:8001/"
 Harness: the test ran to completion.