Origin policy: add runtime enabled feature

https://crbug.com/1057123 will require a runtime enabled feature for use
in the IDL file, in addition to our existing content feature. This adds
that feature and ties it to the content feature.

Bug: 1057123
Change-Id: Ia9db2570a60814525304e8a5965fb5e46b5b8084
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2087954Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Domenic Denicola <domenic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747288}

content/child/runtime_features.cc

@@ -355,6 +355,7 @@ void SetRuntimeFeaturesFromChromiumFeatures() {
           {"LayoutNG", blink::features::kLayoutNG, kUseFeatureState},
           {"LegacyWindowsDWriteFontFallback",
            features::kLegacyWindowsDWriteFontFallback, kUseFeatureState},
+          {"OriginPolicy", features::kOriginPolicy, kUseFeatureState},
           {"ShadowDOMV0", blink::features::kWebComponentsV0Enabled,
            kEnableOnly},
           {"StorageAccessAPI", blink::features::kStorageAccessAPI, kEnableOnly},

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1184,6 +1184,10 @@
       name: "OrientationEvent",
       status: {"Android": "stable"},
     },
+    {
+      name: "OriginPolicy",
+      status: "experimental",
+    },
 
     // Define a sample API for testing integration with the Origin Trials
     // Framework. The sample API is used in both unit and web tests for the