Make <webview> use out-of-process iframe architecture.

components/guest_view/browser/guest_view_message_filter.cc

Index: components/guest_view/browser/guest_view_message_filter.cc
diff --git a/components/guest_view/browser/guest_view_message_filter.cc b/components/guest_view/browser/guest_view_message_filter.cc
index 13835a0ff6441793c8577fb31108bbede147ff38..88720c3c668423de8b1f31ad1f05e22dc47dff8a 100644
--- a/components/guest_view/browser/guest_view_message_filter.cc
+++ b/components/guest_view/browser/guest_view_message_filter.cc
@@ -74,6 +74,8 @@ bool GuestViewMessageFilter::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(GuestViewMessageFilter, message)
     IPC_MESSAGE_HANDLER(GuestViewHostMsg_AttachGuest, OnAttachGuest)
+    IPC_MESSAGE_HANDLER(GuestViewHostMsg_AttachToEmbedderFrame,
+                        OnAttachToEmbedderFrame)
     IPC_MESSAGE_HANDLER(GuestViewHostMsg_ViewCreated, OnViewCreated)
     IPC_MESSAGE_HANDLER(GuestViewHostMsg_ViewGarbageCollected,
                         OnViewGarbageCollected)
@@ -112,4 +114,47 @@ void GuestViewMessageFilter::OnAttachGuest(
                        params);
 }
 
+void GuestViewMessageFilter::OnAttachToEmbedderFrame(
+    int embedder_local_render_frame_id,
+    int element_instance_id,
+    int guest_instance_id,
+    const base::DictionaryValue& params) {
+  auto* manager = GuestViewManager::FromBrowserContext(browser_context_);
+  DCHECK(manager);
+  content::WebContents* guest_web_contents =
+      manager->GetGuestByInstanceIDSafely(guest_instance_id,
+                                          render_process_id_);
+  if (!guest_web_contents)
+    return;
+
+  auto* guest = GuestViewBase::FromWebContents(guest_web_contents);
+  content::WebContents* owner_web_contents = guest->owner_web_contents();
+  DCHECK(owner_web_contents);
+  auto* embedder_frame = RenderFrameHost::FromID(
+      render_process_id_, embedder_local_render_frame_id);
+
+  // Attach this inner WebContents |guest_web_contents| to the outer
+  // WebContents |owner_web_contents|. The outer WebContents's
+  // frame |embedder_frame| hosts the inner WebContents.
+  guest_web_contents->AttachToOuterWebContentsFrame(owner_web_contents,
+                                                    embedder_frame);
+
+  // Update the guest manager about the attachment.
+  // This sets up the embedder and guest pairing information inside
+  // the manager.
+  manager->AttachGuest(render_process_id_, element_instance_id,
+                       guest_instance_id, params);
+
+  owner_web_contents->GetMainFrame()->Send(
+      new GuestViewMsg_AttachToEmbedderFrame_ACK(element_instance_id));
+
+  guest->WillAttach(
+      owner_web_contents, element_instance_id, false,
+      base::Bind(&GuestViewMessageFilter::WillAttachCallback, this, guest));
+}
+
+void GuestViewMessageFilter::WillAttachCallback(GuestViewBase* guest) {
+  guest->DidAttach(MSG_ROUTING_NONE);
+}
+
 }  // namespace guest_view