[IME] Supports options page for each IME instead of single options page for each IME extension.

extensions/common/manifest_constants.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/common/manifest_constants.h"
 
 namespace extensions {
 
 namespace manifest_keys {
 
@@ skipping 33 matching lines @@
 const char kMediaGalleriesHandlers[] = "media_galleries_handlers";
 const char kFileHandlers[] = "file_handlers";
 const char kFileHandlerExtensions[] = "extensions";
 const char kFileHandlerTitle[] = "title";
 const char kFileHandlerTypes[] = "types";
 const char kGlobal[] = "global";
 const char kHideBookmarkButton[] = "hide_bookmark_button";
 const char kHomepageURL[] = "homepage_url";
 const char kIcons[] = "icons";
 const char kId[] = "id";
+const char kImeOptionsPage[] = "options_page";
 const char kImport[] = "import";
 const char kIncognito[] = "incognito";
 const char kIncludeGlobs[] = "include_globs";
 const char kInputComponents[] = "input_components";
 const char kInputView[] = "input_view";
 const char kIsolation[] = "app.isolation";
 const char kJs[] = "js";
 const char kKey[] = "key";
 const char kKeycode[] = "keyCode";
 const char kKioskEnabled[] = "kiosk_enabled";
@@ skipping 623 matching lines @@
 const char kWebRequestConflictsWithLazyBackground[] =
     "The 'webRequest' API cannot be used with event pages.";
 #if defined(OS_CHROMEOS)
 const char kIllegalPlugins[] =
     "Extensions cannot install plugins on Chrome OS";
 #endif
 
 }  // namespace manifest_errors
 
 }  // namespace extensions