Mark Feature Policy-related features as dependent.

This fixes the problem where Feature Policy can be independently
disabled through runtime flags (or chrome://flags), while the features
which depend on it, such as FeaturePolicyForPermissions, remain enabled.

Bug: 806362
Change-Id: Ied92dc74022a02f22a11c3ce68bd62c1aa98eaae
Reviewed-on: https://chromium-review.googlesource.com/893598Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Ian Clelland <iclelland@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532972}

third_party/WebKit/Source/platform/runtime_enabled_features.json5

@@ -400,18 +400,21 @@
     },
     {
       name: "FeaturePolicyAutoplayFeature",
-      status: "stable"
+      status: "stable",
+      depends_on: ["FeaturePolicy"]
     },
     {
       name: "FeaturePolicyExperimentalFeatures",
     },
     {
       name: "FeaturePolicyForPermissions",
-      status: "stable"
+      status: "stable",
+      depends_on: ["FeaturePolicy"]
     },
     {
       name: "FeaturePolicyJavaScriptInterface",
-      status: "experimental"
+      status: "experimental",
+      depends_on: ["FeaturePolicy"]
     },
     {
       name: "FetchRequestCache",