Extension Storage API: expose storage quota information to extensions, via:

chrome/browser/extensions/settings/settings_frontend.cc

 // Copyright (c) 2012 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/settings/settings_frontend.h"
 
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "chrome/browser/extensions/extension_event_names.h"
 #include "chrome/browser/extensions/extension_event_router.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/settings/settings_backend.h"
 #include "chrome/browser/extensions/settings/settings_namespace.h"
 #include "chrome/browser/extensions/settings/settings_leveldb_storage.h"
 #include "chrome/browser/extensions/settings/weak_unlimited_settings_storage.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 
 using content::BrowserThread;
 
 namespace extensions {
 
 namespace {
 
-const SettingsStorageQuotaEnforcer::Limits kSyncQuota = {
-  // 100K should be enough for simple use, but this can be increased as demand
-  // increases.
-  100 * 1024,
-
-  // Sync supports 5k per settings, so be a bit more restrictive than that.
-  2048,
-
-  // Keep low for sync.
-  512
-};
-
-const SettingsStorageQuotaEnforcer::Limits kLocalQuota = {
-  // Same as localStorage (5MB).
-  5 * 1000 * 1024,
-
-  // No need to be restrictive per key here.
-  UINT_MAX,
-
-  // Ditto.
-  UINT_MAX
-};
-
 // Settings change Observer which forwards changes on to the extension
 // processes for |profile| and its incognito partner if it exists.
 class DefaultObserver : public SettingsObserver {
  public:
   explicit DefaultObserver(Profile* profile) : profile_(profile) {}
 
   // SettingsObserver implementation.
   virtual void OnSettingsChanged(
       const std::string& extension_id,
       settings_namespace::Namespace settings_namespace,
@@ skipping 45 matching lines @@
     const SettingsFrontend::StorageCallback& callback,
     SettingsBackend* backend) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   WeakUnlimitedSettingsStorage unlimited_storage(
       backend->GetStorage(extension_id));
   callback.Run(&unlimited_storage);
 }
 
 }  // namespace
 
+// The values in kSyncQuota and kLocalQuota must match those in
+// chrome/common/extensions/api/storage.json
+
+// static
+const SettingsStorageQuotaEnforcer::Limits SettingsFrontend::kSyncQuota = {
+  // 100K should be enough for simple use, but this can be increased as demand
+  // increases.
+  100 * 1024,
+
+  // Sync supports 5k per settings, so be a bit more restrictive than that.
+  2048,
+
+  // Keep low for sync.
+  512
+};
+
+const SettingsStorageQuotaEnforcer::Limits SettingsFrontend::kLocalQuota = {
+  // Same as localStorage (5MB).
+  5 * 1000 * 1024,
+
+  // No need to be restrictive per key here.
+  UINT_MAX,
+
+  // Ditto.
+  UINT_MAX
+};
+
 // Ref-counted container for a SettingsBackend object.
 class SettingsFrontend::BackendWrapper
     : public base::RefCountedThreadSafe<BackendWrapper> {
  public:
   // Creates a new BackendWrapper and initializes it on the FILE thread.
   static scoped_refptr<BackendWrapper> CreateAndInit(
       const scoped_refptr<SettingsStorageFactory>& factory,
       const SettingsStorageQuotaEnforcer::Limits& quota,
       const scoped_refptr<SettingsObserverList>& observers,
       const FilePath& path) {
@@ skipping 209 matching lines @@
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   return observers_;
 }
 
 // BackendWrappers
 
 SettingsFrontend::BackendWrappers::BackendWrappers() {}
 SettingsFrontend::BackendWrappers::~BackendWrappers() {}
 
 }  // namespace extensions