GuestView: Fix message routing across embedder navigations

extensions/browser/guest_view/guest_view_manager.cc

Index: extensions/browser/guest_view/guest_view_manager.cc
diff --git a/extensions/browser/guest_view/guest_view_manager.cc b/extensions/browser/guest_view/guest_view_manager.cc
index 8f6b0dc0bfd27a03ed5d412b3f431aa0adf106a7..f3933c571854e9d0cd331127c613ac7e7ca10c93 100644
--- a/extensions/browser/guest_view/guest_view_manager.cc
+++ b/extensions/browser/guest_view/guest_view_manager.cc
@@ -70,48 +70,25 @@ content::WebContents* GuestViewManager::GetGuestByInstanceIDSafely(
   return GetGuestByInstanceID(guest_instance_id);
 }
 
-void GuestViewManager::AttachGuest(
-    int embedder_render_process_id,
-    int embedder_routing_id,
-    int element_instance_id,
-    int guest_instance_id,
-    const base::DictionaryValue& attach_params) {
-  content::WebContents* guest_web_contents =
-      GetGuestByInstanceIDSafely(guest_instance_id, embedder_render_process_id);
-  if (!guest_web_contents)
-    return;
-
-  auto guest_view = GuestViewBase::FromWebContents(guest_web_contents);
-  DCHECK(guest_view);
-
-  auto rvh = content::RenderViewHost::FromID(embedder_render_process_id,
-                                             embedder_routing_id);
-  // We need to check that rvh is not nullptr because there may be a race
-  // between AttachGuest and destroying the embedder (i.e. when the embedder is
-  // destroyed immediately after the guest is created).
-  if (!rvh)
-    return;
-  auto owner_web_contents = content::WebContents::FromRenderViewHost(rvh);
-  if (!owner_web_contents)
+void GuestViewManager::AttachGuest(int embedder_process_id,
+                                   int element_instance_id,
+                                   int guest_instance_id,
+                                   const base::DictionaryValue& attach_params) {
+  auto guest_view = GuestViewBase::From(embedder_process_id, guest_instance_id);
+  if (!guest_view)
     return;
-  ElementInstanceKey key(owner_web_contents, element_instance_id);
 
+  ElementInstanceKey key(embedder_process_id, element_instance_id);
   auto it = instance_id_map_.find(key);
+  // If there is an existing guest attached to the element, then destroy the
+  // existing guest.
   if (it != instance_id_map_.end()) {
     int old_guest_instance_id = it->second;
-    // Reattachment to the same guest is not currently supported.
     if (old_guest_instance_id == guest_instance_id)
       return;
 
-    auto old_guest_web_contents =
-        GetGuestByInstanceIDSafely(old_guest_instance_id,
-                                   embedder_render_process_id);
-    if (!old_guest_web_contents)
-      return;
-
-    auto old_guest_view =
-        GuestViewBase::FromWebContents(old_guest_web_contents);
-
+    auto old_guest_view = GuestViewBase::From(embedder_process_id,
+                                              old_guest_instance_id);
     old_guest_view->Destroy();
   }
   instance_id_map_[key] = guest_instance_id;
@@ -119,24 +96,21 @@ void GuestViewManager::AttachGuest(
   guest_view->SetAttachParams(attach_params);
 }
 
-void GuestViewManager::DetachGuest(GuestViewBase* guest,
-                                   int element_instance_id) {
+void GuestViewManager::DetachGuest(GuestViewBase* guest) {
   if (!guest->attached())
     return;
 
-  ElementInstanceKey key(guest->owner_web_contents(), element_instance_id);
-  auto it = instance_id_map_.find(key);
-  // There's nothing to do if this key does not exist in the map.
-  if (it == instance_id_map_.end())
+  auto reverse_it = reverse_instance_id_map_.find(guest->guest_instance_id());
+  if (reverse_it == reverse_instance_id_map_.end())
     return;
 
-  int guest_instance_id = it->second;
-  instance_id_map_.erase(key);
+  const ElementInstanceKey& key = reverse_it->second;
 
-  auto reverse_it = reverse_instance_id_map_.find(guest->guest_instance_id());
-  DCHECK(reverse_it != reverse_instance_id_map_.end());
-  DCHECK(reverse_it->second == key);
-  reverse_instance_id_map_.erase(guest_instance_id);
+  auto it = instance_id_map_.find(key);
+  DCHECK(it != instance_id_map_.end());
+
+  reverse_instance_id_map_.erase(reverse_it);
+  instance_id_map_.erase(it);
 }
 
 int GuestViewManager::GetNextInstanceID() {
@@ -170,9 +144,9 @@ content::WebContents* GuestViewManager::CreateGuestWithWebContentsParams(
 }
 
 content::WebContents* GuestViewManager::GetGuestByInstanceID(
-    content::WebContents* owner_web_contents,
+    int owner_process_id,
     int element_instance_id) {
-  int guest_instance_id = GetGuestInstanceIDForElementID(owner_web_contents,
+  int guest_instance_id = GetGuestInstanceIDForElementID(owner_process_id,
                                                          element_instance_id);
   if (guest_instance_id == guestview::kInstanceIDNone)
     return nullptr;
@@ -180,11 +154,10 @@ content::WebContents* GuestViewManager::GetGuestByInstanceID(
   return GetGuestByInstanceID(guest_instance_id);
 }
 
-int GuestViewManager::GetGuestInstanceIDForElementID(
-    content::WebContents* owner_web_contents,
-    int element_instance_id) {
+int GuestViewManager::GetGuestInstanceIDForElementID(int owner_process_id,
+                                                     int element_instance_id) {
   auto iter = instance_id_map_.find(
-      ElementInstanceKey(owner_web_contents, element_instance_id));
+      ElementInstanceKey(owner_process_id, element_instance_id));
   if (iter == instance_id_map_.end())
     return guestview::kInstanceIDNone;
   return iter->second;