Introduce content-side Feature Policy object and maintain in parallel with renderer policy.

third_party/WebKit/public/platform/WebFeaturePolicy.h

Index: third_party/WebKit/public/platform/WebFeaturePolicy.h
diff --git a/third_party/WebKit/public/platform/WebFeaturePolicy.h b/third_party/WebKit/public/platform/WebFeaturePolicy.h
index b0394a552ad220cfd2c2f08f38566d8787d29180..04a626a48e607daeef15d695b29350c085eee89e 100644
--- a/third_party/WebKit/public/platform/WebFeaturePolicy.h
+++ b/third_party/WebKit/public/platform/WebFeaturePolicy.h
@@ -11,6 +11,25 @@
 
 namespace blink {
 
+enum class WebFeaturePolicyFeature {
+  NotFound = 0,
+  DocumentCookie,
+  DocumentDomain,
+  DocumentWrite,
+  Geolocation,
+  Fullscreen,
+  MidiFeature,
+  Notifications,
+  Payment,
+  Push,
+  SyncScript,
+  SyncXHR,
+  Usermedia,
+  Vibrate,
+  WebRTC,
+  LAST_FEATURE = WebRTC
+};
+
 struct WebParsedFeaturePolicyDeclaration {
   WebParsedFeaturePolicyDeclaration() : matchesAllOrigins(false) {}
   WebString featureName;