[Not Ready To Comimt] Add chrome://flags/#enable-off-main-thread-fetch

chrome/browser/flag_descriptions.cc

 // Copyright 2017 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/flag_descriptions.h"
 
 namespace flag_descriptions {
 
 //  Material Design version of chrome://bookmarks
 
@@ skipping 81 matching lines @@
     R"*(comparison purposes.)*";
 
 const char kSpeculativePrefetchName[] = "Speculative Prefetch";
 
 const char kSpeculativePrefetchDescription[] =
     R"*("Speculative Prefetch" fetches likely resources early to improve )*"
     R"*(load times, based on a local database (see chrome://predictors). )*"
     R"*("Learning" means that only the database construction is enabled, )*"
     R"*("Prefetching" that learning and prefetching are enabled.)*";
 
+const char kOffMainThreadFetchName[] =
+    "Experimental resource fetch optimizations for workers";
+
+const char kOffMainThreadFetchDescription[] =
+    "If enabled, the resource fetch in worker threads will not be blocked by "
+    "the busy main thread.";
+
 //  Force Tablet Mode
 
 const char kForceTabletModeName[] = "Force Tablet Mode";
 
 const char kForceTabletModeDescription[] =
     R"*(This flag can be used to force a certain mode on to a chromebook, )*"
     R"*(despite its current orientation. "TouchView" means that the )*"
     R"*(chromebook will act as if it were in touch view mode. "Clamshell" )*"
     R"*(means that the chromebook will act as if it were in clamshell )*"
     R"*(mode . "Auto" means that the chromebook will alternate between )*"
@@ skipping 2802 matching lines @@
 const char kEnableEhvInputName[] =
     "Emoji, handwriting and voice input on opt-in IME menu";
 
 const char kEnableEhvInputDescription[] =
     "Enable access to emoji, handwriting and voice input form opt-in IME "
     "menu.";
 
 #endif  // #if defined(OS_CHROMEOS)
 
 }  // namespace flag_descriptions