This patch improves the way that GuestViewManager tracks the destruction of GuestView embedders.

components/guest_view/browser/guest_view_manager.h

Index: components/guest_view/browser/guest_view_manager.h
diff --git a/components/guest_view/browser/guest_view_manager.h b/components/guest_view/browser/guest_view_manager.h
index 5364edefcb920e6047d70c503f42e75ed56552c0..0a6725355f9ec2eeb95ffa1267892b92014bafe0 100644
--- a/components/guest_view/browser/guest_view_manager.h
+++ b/components/guest_view/browser/guest_view_manager.h
@@ -132,6 +132,8 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
   friend class GuestViewEvent;
   friend class GuestViewMessageFilter;
 
+  class EmbedderRenderProcessHostObserver;
+
   // These methods are virtual so that they can be overriden in tests.
 
   virtual void AddGuest(int guest_instance_id,
@@ -139,8 +141,8 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
   virtual void RemoveGuest(int guest_instance_id);
 
   // This method is called when the embedder process with ID
-  // |embedder_process_id| is about to be destroyed.
-  virtual void EmbedderWillBeDestroyed(int embedder_process_id);
+  // |embedder_process_id| has been destroyed.
+  virtual void EmbedderProcessDestroyed(int embedder_process_id);
 
   // Called when a GuestView has been created in JavaScript.
   virtual void ViewCreated(int embedder_process_id,
@@ -151,6 +153,15 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
   virtual void ViewGarbageCollected(int embedder_process_id,
                                     int view_instance_id);
 
+  // Calls all destruction callbacks registered for the GuestView identified by
+  // |embedder_process_id| and |view_instance_id|.
+  void CallViewDestructionCallbacks(int embedder_process_id,
+                                    int view_instance_id);
+
+  // Calls all destruction callbacks registered for GuestViews in the embedder
+  // with ID |embedder_process_id|.
+  void CallViewDestructionCallbacks(int embedder_process_id);
+
   // Creates a guest of the provided |view_type|.
   GuestViewBase* CreateGuestInternal(content::WebContents* owner_web_contents,
                                      const std::string& view_type);
@@ -215,7 +226,8 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
 
   using GuestViewCreateFunction =
       base::Callback<GuestViewBase*(content::WebContents*)>;
-  using GuestViewCleanUpFunction = base::Callback<void(int, int)>;
+  using GuestViewCleanUpFunction =
+      base::Callback<void(content::BrowserContext*, int, int)>;
   struct GuestViewData {
     GuestViewData(const GuestViewCreateFunction& create_function,
                   const GuestViewCleanUpFunction& cleanup_function);
@@ -248,6 +260,9 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
   using CallbacksForEachEmbedderID = std::map<int, CallbacksForEachViewID> ;
   CallbacksForEachEmbedderID view_destruction_callback_map_;
 
+  ScopedVector<EmbedderRenderProcessHostObserver>
+      embedder_render_process_host_observers_;
+
   DISALLOW_COPY_AND_ASSIGN(GuestViewManager);
 };