Remove InstallTracker's extension installed, uninstalled observers.

chrome/browser/extensions/shared_module_service.cc

Index: chrome/browser/extensions/shared_module_service.cc
diff --git a/chrome/browser/extensions/shared_module_service.cc b/chrome/browser/extensions/shared_module_service.cc
index 78e9ab74e21c6c06c95f8661e9c110e776fb5aea..22c9e25117e781595423f0f681d031c80e6ae2b0 100644
--- a/chrome/browser/extensions/shared_module_service.cc
+++ b/chrome/browser/extensions/shared_module_service.cc
@@ -8,7 +8,6 @@
 
 #include "base/version.h"
 #include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/extensions/install_tracker.h"
 #include "chrome/browser/extensions/pending_extension_manager.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "extensions/browser/extension_registry.h"
@@ -25,17 +24,15 @@ typedef std::list<SharedModuleInfo::ImportInfo> ImportInfoList;
 }  // namespace
 
 SharedModuleService::SharedModuleService(content::BrowserContext* context)
-    : context_(context), observing_(false) {
-  InstallTracker::Get(context_)->AddObserver(this);
+    : extension_registry_observer_(this), browser_context_(context) {
+  extension_registry_observer_.Add(ExtensionRegistry::Get(browser_context_));
 }
 
 SharedModuleService::~SharedModuleService() {
-  if (observing_)
-    InstallTracker::Get(context_)->RemoveObserver(this);
 }
 
 SharedModuleService::ImportStatus SharedModuleService::CheckImports(
-    const extensions::Extension* extension,
+    const Extension* extension,
     ImportInfoList* missing_modules,
     ImportInfoList* outdated_modules) {
   DCHECK(extension);
@@ -44,7 +41,7 @@ SharedModuleService::ImportStatus SharedModuleService::CheckImports(
 
   ImportStatus status = IMPORT_STATUS_OK;
 
-  ExtensionRegistry* registry = ExtensionRegistry::Get(context_);
+  ExtensionRegistry* registry = ExtensionRegistry::Get(browser_context_);
   const ImportInfoVector& imports = SharedModuleInfo::GetImports(extension);
   for (ImportInfoVector::const_iterator iter = imports.begin();
        iter != imports.end();
@@ -87,7 +84,7 @@ SharedModuleService::ImportStatus SharedModuleService::SatisfyImports(
       CheckImports(extension, &missing_modules, &outdated_modules);
 
   ExtensionService* service =
-      ExtensionSystem::Get(context_)->extension_service();
+      ExtensionSystem::Get(browser_context_)->extension_service();
 
   PendingExtensionManager* pending_extension_manager =
       service->pending_extension_manager();
@@ -112,9 +109,9 @@ scoped_ptr<const ExtensionSet> SharedModuleService::GetDependentExtensions(
   scoped_ptr<ExtensionSet> dependents(new ExtensionSet());
 
   if (SharedModuleInfo::IsSharedModule(extension)) {
-    ExtensionRegistry* registry = ExtensionRegistry::Get(context_);
+    ExtensionRegistry* registry = ExtensionRegistry::Get(browser_context_);
     ExtensionService* service =
-        ExtensionSystem::Get(context_)->extension_service();
+        ExtensionSystem::Get(browser_context_)->extension_service();
 
     ExtensionSet set_to_check;
     set_to_check.InsertAll(registry->enabled_extensions());
@@ -133,14 +130,16 @@ scoped_ptr<const ExtensionSet> SharedModuleService::GetDependentExtensions(
   return dependents.PassAs<const ExtensionSet>();
 }
 
-void SharedModuleService::PruneSharedModulesOnUninstall(
+void SharedModuleService::OnExtensionUninstalled(
+    content::BrowserContext* browser_context,
     const Extension* extension) {
+  // Uninstalls shared modules that were only referenced by |extension|.
   if (!SharedModuleInfo::ImportsModules(extension))
     return;
 
-  ExtensionRegistry* registry = ExtensionRegistry::Get(context_);
+  ExtensionRegistry* registry = ExtensionRegistry::Get(browser_context_);
   ExtensionService* service =
-      ExtensionSystem::Get(context_)->extension_service();
+      ExtensionSystem::Get(browser_context_)->extension_service();
 
   const ImportInfoVector& imports = SharedModuleInfo::GetImports(extension);
   for (ImportInfoVector::const_iterator iter = imports.begin();
@@ -161,13 +160,4 @@ void SharedModuleService::PruneSharedModulesOnUninstall(
   }
 }
 
-void SharedModuleService::OnExtensionUninstalled(const Extension* extension) {
-  PruneSharedModulesOnUninstall(extension);
-}
-
-void SharedModuleService::OnShutdown() {
-  InstallTracker::Get(context_)->RemoveObserver(this);

[not at google - send to devlin, 2014/06/10 18:12:41]

so.... it does seem like this is safe to remove, because SharedModuleService is
owned by ExtensionService, which has a shorter lifetime than ExtensionRegistry.

so, hoping for the best here - but if this is a problem then we may need to add
back the OnShutdown behaviour.

[limasdf, 2014/06/11 00:26:00]

yep, please let me know if there's problem about this.

-  observing_ = false;
-}
-
 }  // namespace extensions