Add a function triggering extension installed to ExtensionRegistryObserver

extensions/browser/extension_registry.cc

 // Copyright 2013 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 "extensions/browser/extension_registry.h"
 
 #include "base/strings/string_util.h"
 #include "extensions/browser/extension_registry_factory.h"
 #include "extensions/browser/extension_registry_observer.h"
 
@@ skipping 35 matching lines @@
 
 void ExtensionRegistry::TriggerOnUnloaded(
     const Extension* extension,
     UnloadedExtensionInfo::Reason reason) {
   DCHECK(!enabled_extensions_.Contains(extension->id()));
   FOR_EACH_OBSERVER(ExtensionRegistryObserver,
                     observers_,
                     OnExtensionUnloaded(browser_context_, extension, reason));
 }
 
+void ExtensionRegistry::TriggerOnWillBeInstalled(const Extension* extension,
+                                                 bool is_update,
+                                                 const std::string& old_name) {
+  DCHECK(!GenerateInstalledExtensionsSet()->Contains(extension->id()));

[limasdf, 2014/05/17 13:15:10]

I'm going to remove this DCHECK.
Because when service reloads extension by |ReloadExtension|,
service just make the existing extension as DISABLED status. and then send
INSTALLED notification.

I catched this issue while running unittest.
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ext...

+  FOR_EACH_OBSERVER(ExtensionRegistryObserver,
+                    observers_,
+                    OnExtensionWillBeInstalled(
+                        browser_context_, extension, is_update, old_name));
+}
+
 const Extension* ExtensionRegistry::GetExtensionById(const std::string& id,
                                                      int include_mask) const {
   std::string lowercase_id = StringToLowerASCII(id);
   if (include_mask & ENABLED) {
     const Extension* extension = enabled_extensions_.GetByID(lowercase_id);
     if (extension)
       return extension;
   }
   if (include_mask & DISABLED) {
     const Extension* extension = disabled_extensions_.GetByID(lowercase_id);
@@ skipping 60 matching lines @@
     const ExtensionSet::ModificationCallback& callback) {
   disabled_extensions_.set_modification_callback(callback);
 }
 
 void ExtensionRegistry::Shutdown() {
   // Release references to all Extension objects in the sets.
   ClearAll();
 }
 
 }  // namespace extensions