Add skia extension to allow setting default fontmgr on linux. Use it to allow the linux blimp clien…

blimp/client/core/switches/blimp_client_switches.cc

 // Copyright 2016 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 "blimp/client/core/switches/blimp_client_switches.h"
 
 namespace blimp {
 namespace switches {
 
 const char kEnableBlimp[] = "enable-blimp";
 
 const char kEngineCertPath[] = "engine-cert-path";
 
 // Specifies the engine's IP address. Must be used in conjunction with
 // --engine-port and --engine-transport.
 // This is the same command line flag as ENGINE_IP in
 // android/java/src/org/chromium/blimp/core/BlimpClientSwitches.java
 const char kEngineIP[] = "engine-ip";
 
 const char kEnginePort[] = "engine-port";
 
 const char kEngineTransport[] = "engine-transport";
 
 const char kDownloadWholeDocument[] = "download-whole-document";
 
+const char kAndroidFontsPath[] = "android-fonts-path";
+
 }  // namespace switches
 }  // namespace blimp