Replicate feature policy headers to remote frames

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 e37dd7be76d451a134919bc6406a786bccc0a169..58f7c3dce2d40e15f20b68f5318e0b04c2228787 100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -255,6 +255,14 @@ void FrameTreeNode::SetFrameName(const std::string& name,
   replication_state_.unique_name = unique_name;
 }
 
+void FrameTreeNode::SetFeaturePolicyHeader(const std::string& header) {
+  replication_state_.feature_policy_header = header;
+}
+
+void FrameTreeNode::ResetFeaturePolicy() {
+  replication_state_.feature_policy_header = "";

[dcheng, 2016/11/20 21:04:12]

Nit: std::string::clear() is slightly cheaper.

Btw, how big can these headers get? Do we explicitly want to release as much
storage as possible here with something like STLClearObject() from stl_util.h?

[iclelland, 2016/11/21 05:05:33]

Done.
There's no explicit limit in the spec; a site could provide a policy with a
large number of explicitly-authorized domains for each feature. We should
probably have a sanity limit of some small number of kilobytes.

+}
+
 void FrameTreeNode::AddContentSecurityPolicy(
     const ContentSecurityPolicyHeader& header) {
   replication_state_.accumulated_csp_headers.push_back(header);