Feature policy: Add basic algorithm for supporting frame policies.

content/common/feature_policy/feature_policy.cc

Index: content/common/feature_policy/feature_policy.cc
diff --git a/content/common/feature_policy/feature_policy.cc b/content/common/feature_policy/feature_policy.cc
index c4875a9c01fc463b1327854fbc880fff326ea103..2ca84464dbaf2217784f87294796fab567d585bc 100644
--- a/content/common/feature_policy/feature_policy.cc
+++ b/content/common/feature_policy/feature_policy.cc
@@ -109,8 +109,10 @@ bool FeaturePolicy::Whitelist::Contains(const url::Origin& origin) const {
 // static
 std::unique_ptr<FeaturePolicy> FeaturePolicy::CreateFromParentPolicy(
     const FeaturePolicy* parent_policy,
+    const ParsedFeaturePolicyHeader* frame_policy,
     const url::Origin& origin) {
-  return CreateFromParentPolicy(parent_policy, origin, GetDefaultFeatureList());
+  return CreateFromParentPolicy(parent_policy, frame_policy, origin,
+                                GetDefaultFeatureList());
 }
 
 bool FeaturePolicy::IsFeatureEnabledForOrigin(
@@ -165,6 +167,7 @@ FeaturePolicy::~FeaturePolicy() {}
 // static
 std::unique_ptr<FeaturePolicy> FeaturePolicy::CreateFromParentPolicy(
     const FeaturePolicy* parent_policy,
+    const ParsedFeaturePolicyHeader* frame_policy,
     const url::Origin& origin,
     const FeaturePolicy::FeatureList& features) {
   std::unique_ptr<FeaturePolicy> new_policy =
@@ -176,10 +179,33 @@ std::unique_ptr<FeaturePolicy> FeaturePolicy::CreateFromParentPolicy(
     } else {
       new_policy->inherited_policies_[feature.first] = false;
     }
+    if (frame_policy) {

[raymes, 2017/02/20 02:20:17]

nit: we should be consistent with brackets around single-line if's.
Unfortunately the style guide says nothing, but at least within files we should
try to be consistent :)

[iclelland, 2017/02/21 19:51:05]

Done.

+      new_policy->AddFramePolicy(parent_policy, frame_policy);
+    }
   }
   return new_policy;
 }
 
+void FeaturePolicy::AddFramePolicy(
+    const FeaturePolicy* parent_policy,
+    const ParsedFeaturePolicyHeader* frame_policy) {
+  DCHECK(parent_policy);
+  DCHECK(frame_policy);
+  for (const ParsedFeaturePolicyDeclaration& parsed_declaration :
+       *frame_policy) {
+    blink::WebFeaturePolicyFeature feature =
+        FeatureForName(parsed_declaration.feature_name, feature_list_);
+    if (feature == blink::WebFeaturePolicyFeature::NotFound)
+      continue;
+    if (WhitelistFromDeclaration(parsed_declaration)->Contains(origin_) &&

[raymes, 2017/02/20 02:20:17]

nit: I know it will be specc'd but maybe a comment explaining the reasoning here
would help. e.g.
// If a feature is enabled in the parent frame and the parent chooses to
delegate it to a child frame
// using the iframe attribute, then the feature should be enabled in the child
frame.

[iclelland, 2017/02/21 19:51:05]

Done. (And in blink-side implementation as well)

+        parent_policy->IsFeatureEnabled(feature)) {
+      inherited_policies_[feature] = true;
+    } else {
+      inherited_policies_[feature] = false;
+    }
+  }
+}
+
 // static
 const FeaturePolicy::FeatureList& FeaturePolicy::GetDefaultFeatureList() {
   CR_DEFINE_STATIC_LOCAL(