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

content/browser/frame_host/frame_tree_node.cc

Index: content/browser/frame_host/frame_tree_node.cc
diff --git a/content/browser/frame_host/frame_tree_node.cc b/content/browser/frame_host/frame_tree_node.cc
index e1e749223562f4aad3a84e5403c12e52fbcb0e85..8944f279d17e8b4b1984ec6bc4edc0c899bce6ef 100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -258,11 +258,20 @@ void FrameTreeNode::SetFrameName(const std::string& name,
 
 void FrameTreeNode::SetFeaturePolicyHeader(
     const ParsedFeaturePolicyHeader& parsed_header) {
+  ResetFeaturePolicy();
   replication_state_.feature_policy_header = parsed_header;
+  feature_policy_->SetHeaderPolicy(parsed_header);
 }
 
 void FrameTreeNode::ResetFeaturePolicy() {
   replication_state_.feature_policy_header.clear();
+  if (parent()) {
+    feature_policy_ = FeaturePolicy::CreateFromParentPolicy(
+        parent()->feature_policy_.get(), current_origin());
+  } else {
+    feature_policy_ =
+        FeaturePolicy::CreateFromParentPolicy(nullptr, current_origin());
+  }

[raymes, 2017/02/01 22:42:20]

optional: alternatively:
FeaturePolicy* parent_policy = parent() ? parent()->feature_policy_.get() :
nullptr;
...

[iclelland, 2017/02/03 16:38:29]

Done.

 }
 
 void FrameTreeNode::AddContentSecurityPolicy(