Remove the mojo serial interfaces and related infrastructure.

extensions/common/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 source_set("common_constants") {
   sources = [
     "constants.cc",
     "constants.h",
   ]
 
   # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 }
 
 if (enable_extensions) {
   mojom("mojo") {
     sources = [
       "mojo/keep_alive.mojom",
-      "mojo/stash.mojom",
     ]
     if (proprietary_codecs && enable_wifi_display) {
       sources += [ "mojo/wifi_display_session_service.mojom" ]
     }
 
     use_new_wrapper_types = false
   }
 
   # This must be a static library because extensions common depends on
   # GetTrustedICAPublicKey in extensions/browser which isn't always linked
@@ skipping 323 matching lines @@
       "//extensions/strings",
       "//ipc",
       "//testing/gmock",
       "//testing/gtest",
       "//ui/base",
       "//ui/gfx",
       "//url",
     ]
   }
 }  # enable_extensions