extensions: Abstract out install delay strategy

chrome/browser/extensions/shared_module_service.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/shared_module_service.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 116 matching lines @@
          ++iter) {
       if (SharedModuleInfo::ImportsExtensionById(iter->get(),
                                                  extension->id())) {
         dependents->Insert(*iter);
       }
     }
   }
   return dependents;
 }
 
+InstallGate::Action SharedModuleService::ShouldDelay(const Extension* extension,
+                                                     bool install_immediately) {
+  ImportStatus status = SatisfyImports(extension);
+  switch (status) {
+    case IMPORT_STATUS_OK:
+      return INSTALL;
+    case IMPORT_STATUS_UNSATISFIED:
+      return DELAY;
+    case IMPORT_STATUS_UNRECOVERABLE:
+      return ABORT;
+  }
+
+  NOTREACHED();
+  return INSTALL;
+}
+
 void SharedModuleService::PruneSharedModules() {
   ExtensionRegistry* registry = ExtensionRegistry::Get(browser_context_);
   ExtensionService* service =
       ExtensionSystem::Get(browser_context_)->extension_service();
 
   ExtensionSet set_to_check;
   set_to_check.InsertAll(registry->enabled_extensions());
   set_to_check.InsertAll(registry->disabled_extensions());
   set_to_check.InsertAll(*service->delayed_installs());
 
@@ skipping 42 matching lines @@
     extensions::UninstallReason reason) {
   // Do not call PruneSharedModules() for an uninstall that we were responsible
   // for.
   if (reason == extensions::UNINSTALL_REASON_ORPHANED_SHARED_MODULE)
     return;
 
   PruneSharedModules();
 }
 
 }  // namespace extensions