Put more files under the enable_service_discovery build flag.

chrome/browser/devtools/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.
 
 if (!is_android) {
+  import("//build/config/features.gni")
   import("//tools/grit/grit_rule.gni")
 }
 
 action("devtools_protocol_constants") {
   script = "devtools_protocol_constants_generator.py"
 
   blink_protocol = "//third_party/WebKit/Source/devtools/protocol.json"
   browser_protocol = "//content/browser/devtools/browser_protocol.json"
   inputs = [
     blink_protocol,
@@ skipping 69 matching lines @@
       "chrome_devtools_discovery_provider.cc",
       "chrome_devtools_discovery_provider.h",
       "device/adb/adb_client_socket.cc",
       "device/adb/adb_client_socket.h",
       "device/adb/adb_device_provider.cc",
       "device/adb/adb_device_provider.h",
       "device/android_device_info_query.cc",
       "device/android_device_manager.cc",
       "device/android_device_manager.h",
       "device/android_web_socket.cc",
-      "device/cast_device_provider.cc",
-      "device/cast_device_provider.h",
       "device/devtools_android_bridge.cc",
       "device/devtools_android_bridge.h",
       "device/port_forwarding_controller.cc",
       "device/port_forwarding_controller.h",
       "device/tcp_device_provider.cc",
       "device/tcp_device_provider.h",
       "device/usb/android_rsa.cc",
       "device/usb/android_rsa.h",
       "device/usb/android_usb_device.cc",
       "device/usb/android_usb_device.h",
@@ skipping 19 matching lines @@
       "devtools_toggle_action.h",
       "devtools_ui_bindings.cc",
       "devtools_ui_bindings.h",
       "devtools_window.cc",
       "devtools_window.h",
       "global_confirm_info_bar.cc",
       "global_confirm_info_bar.h",
       "remote_debugging_server.cc",
       "remote_debugging_server.h",
     ]
+    if (enable_service_discovery) {
+      sources += [
+        "device/cast_device_provider.cc",
+        "device/cast_device_provider.h",
+      ]
+    }
   }
 }