Add a function to add extra headers from NavigationThrottle

content/browser/frame_host/navigation_handle_impl.cc

Index: content/browser/frame_host/navigation_handle_impl.cc
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index 8904071971d98abe681d66e45323855444bb4f87..59c4d21f6fd95dfd86d893b91691707334b28246 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -21,7 +21,8 @@ namespace {
 
 void UpdateThrottleCheckResult(
     NavigationThrottle::ThrottleCheckResult* to_update,
-    NavigationThrottle::ThrottleCheckResult result) {
+    NavigationThrottle::ThrottleCheckResult result,
+    const NavigationHandleImpl::ExtraHeadersList& headers) {
   *to_update = result;
 }
 
@@ -217,6 +218,15 @@ void NavigationHandleImpl::InitServiceWorkerHandle(
       new ServiceWorkerNavigationHandle(service_worker_context));
 }
 
+void NavigationHandleImpl::AddExtraHeader(const std::string& name,
+                                          const std::string& value) {
+  // Only set headers during throttle checks, when the handler of the request
+  // will be able to add them to the network request.
+  DCHECK(!complete_callback_.is_null());

[davidben, 2015/12/03 23:44:56]

Perhaps also DCHECK on state_, in case you add a new throttle check later?

+  extra_headers_to_add_.push_back(
+      std::pair<std::string, std::string>(name, value));
+}
+
 void NavigationHandleImpl::WillStartRequest(
     bool is_post,
     const Referrer& sanitized_referrer,
@@ -376,9 +386,10 @@ void NavigationHandleImpl::RunCompleteCallback(
     NavigationThrottle::ThrottleCheckResult result) {
   DCHECK(result != NavigationThrottle::DEFER);
   if (!complete_callback_.is_null())
-    complete_callback_.Run(result);
+    complete_callback_.Run(result, extra_headers_to_add_);
 
   complete_callback_.Reset();
+  extra_headers_to_add_.clear();
 }
 
 }  // namespace content