Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

content/browser/frame_host/frame_tree_node.h

 // 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.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_
 #define CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 119 matching lines @@
 
   // Sets the last committed URL for this frame and updates
   // has_committed_real_load accordingly.
   void SetCurrentURL(const GURL& url);
 
   // Returns true iff SetCurrentURL has been called with a non-blank URL.
   bool has_committed_real_load() const {
     return has_committed_real_load_;
   }
 
+  // Returns whether the frame's owner element in the parent frame is collapsed
+  // as per request by the client, i.e. it should not appear in the layout.
+  bool is_frame_owner_collapsed() const { return is_frame_owner_collapsed_; }
+
+  // Sets whether to collapse, i.e. exclude from the layout, the frame's owner
+  // element in the parent frame. Not applicable to main frames, and will have
+  // no effect unless the child frame is embedded using an <iframe> element.

[clamy, 2017/01/18 15:10:55]

It's not very clear to me while reading this description what this means. Does
it mean that the parent frame won't show or this one?

[engedy, 2017/02/17 18:09:25]

I have done some wordsmithing, please take another look.

+  void SetFrameOwnerCollapsedState(bool collapsed);
+
   // Returns the origin of the last committed page in this frame.
   // WARNING: To get the last committed origin for a particular
   // RenderFrameHost, use RenderFrameHost::GetLastCommittedOrigin() instead,
   // which will behave correctly even when the RenderFrameHost is not the
   // current one for this frame (such as when it's pending deletion).
   const url::Origin& current_origin() const {
     return replication_state_.origin;
   }
 
   // Set the current origin and notify proxies about the update.
@@ skipping 189 matching lines @@
   // is disowned.
   std::unique_ptr<OpenerDestroyedObserver> opener_observer_;
 
   // The immediate children of this specific frame.
   std::vector<std::unique_ptr<FrameTreeNode>> children_;
 
   // Whether this frame has committed any real load, replacing its initial
   // about:blank page.
   bool has_committed_real_load_;
 
+  // Whether the frame's owner element in the parent frame is collapsed, i.e. it
+  // does not appear in the layout. Always false for main frames, and has have
+  // no effect unless the child frame is embedded using an <iframe> element.
+  bool is_frame_owner_collapsed_;
+
   // Track information that needs to be replicated to processes that have
   // proxies for this frame.
   FrameReplicationState replication_state_;
 
   // Track the pending sandbox flags for this frame.  When a parent frame
   // dynamically updates sandbox flags in the <iframe> element for a child
   // frame, these updated flags are stored here and are transferred into
   // replication_state_.sandbox_flags when they take effect on the next frame
   // navigation.
   blink::WebSandboxFlags pending_sandbox_flags_;
@@ skipping 23 matching lines @@
   // browser process activities to this node (when possible).  It is unrelated
   // to the core logic of FrameTreeNode.
   FrameTreeNodeBlameContext blame_context_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameTreeNode);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_