Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

content/browser/frame_host/render_frame_host_manager.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/frame_host/render_frame_host_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 912 matching lines @@
     blink::WebInsecureRequestPolicy policy) {
   if (!SiteIsolationPolicy::AreCrossProcessFramesPossible())
     return;
 
   for (const auto& pair : proxy_hosts_) {
     pair.second->Send(new FrameMsg_EnforceInsecureRequestPolicy(
         pair.second->GetRoutingID(), policy));
   }
 }
 
+void RenderFrameHostManager::OnDidChangeCollapsedState(bool collapsed) {
+  DCHECK(frame_tree_node_->parent());
+  SiteInstance* parent_site_instance =
+      frame_tree_node_->parent()->current_frame_host()->GetSiteInstance();
+
+  // There will be no proxy to represent the pending or speculative RFHs in the
+  // parent's SiteInstance until the provisional load is committed, but the old
+  // RFH is not swapped out before that happens either, so we can talk to the
+  // FrameOwner in the parent via the child's current RenderFrame at any time.
+  DCHECK(current_frame_host());
+  if (current_frame_host()->GetSiteInstance() == parent_site_instance) {
+    current_frame_host()->Send(
+        new FrameMsg_Collapse(current_frame_host()->GetRoutingID(), collapsed));
+  } else {
+    RenderFrameProxyHost* proxy_to_parent = GetProxyToParent();

[alexmos, 2017/04/11 06:00:29]

optional: you could just use GetRenderFrameProxyHost(parent_site_instance) here
to avoid repeating the parent SiteInstance lookup.  (I also find our name for
GetProxyToParent pretty confusing :) )

[engedy, 2017/04/11 08:06:17]

Nice, done!

+    proxy_to_parent->Send(
+        new FrameMsg_Collapse(proxy_to_parent->GetRoutingID(), collapsed));
+  }
+}
+
 void RenderFrameHostManager::OnDidUpdateFrameOwnerProperties(
     const FrameOwnerProperties& properties) {
   if (!SiteIsolationPolicy::AreCrossProcessFramesPossible())
     return;
 
   // FrameOwnerProperties exist only for frames that have a parent.
   CHECK(frame_tree_node_->parent());
   SiteInstance* parent_instance =
       frame_tree_node_->parent()->current_frame_host()->GetSiteInstance();
 
@@ skipping 1865 matching lines @@
           delegate_->IsHidden()) {
     if (delegate_->IsHidden()) {
       render_frame_host_->GetView()->Hide();
     } else {
       render_frame_host_->GetView()->Show();
     }
   }
 }
 
 }  // namespace content