[Extensions] Rework inline installation observation

chrome/browser/extensions/tab_helper.h

Index: chrome/browser/extensions/tab_helper.h
diff --git a/chrome/browser/extensions/tab_helper.h b/chrome/browser/extensions/tab_helper.h
index c3d368ec5f8c004cb028ad4aed5fa194cc899df4..cdcf17fdbb78b45c30172f9c02db948998151f08 100644
--- a/chrome/browser/extensions/tab_helper.h
+++ b/chrome/browser/extensions/tab_helper.h
@@ -126,6 +126,8 @@ class TabHelper : public content::WebContentsObserver,
       WebstoreInlineInstallerFactory* factory);
 
  private:
+  class InlineInstallObserver;
+
   // Utility function to invoke member functions on all relevant
   // ContentRulesRegistries.
   template <class Func>
@@ -198,6 +200,7 @@ class TabHelper : public content::WebContentsObserver,
   // WebstoreStandaloneInstaller::Callback.
   void OnInlineInstallComplete(int install_id,
                                int return_route_id,
+                               const std::string& extension_id,
                                bool success,
                                const std::string& error,
                                webstore_install::Result result);
@@ -205,6 +208,7 @@ class TabHelper : public content::WebContentsObserver,
   // ExtensionReenabler::Callback.
   void OnReenableComplete(int install_id,
                           int return_route_id,
+                          const std::string& extension_id,
                           ExtensionReenabler::ReenableResult result);
 
   // content::NotificationObserver.
@@ -270,6 +274,12 @@ class TabHelper : public content::WebContentsObserver,
   ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
       registry_observer_;
 
+  std::map<std::string, std::unique_ptr<InlineInstallObserver>>

[lazyboy, 2016/06/29 21:03:04]

Add comment describing this member. or maybe use ExtensionId instead of
std::string to self describe. 

[Devlin, 2016/06/29 22:32:09]

Done. Opted against ExtensionId because a) it would involve #including the
heavy-weight extension.h file* and b) it's inconsistent with the rest of this
file.

* We should probably pull it out into extension_id.h
** We should probably fix that, too, but out of scope for this change.

[lazyboy, 2016/06/29 23:10:27]

Acknowledged.

+      install_observers_;
+
+  // The set of extension ids that are currently being installed.
+  std::set<std::string> pending_inline_installations_;
+
   // Vend weak pointers that can be invalidated to stop in-progress loads.
   base::WeakPtrFactory<TabHelper> image_loader_ptr_factory_;