DesktopCaptureDevice is available when webrtc is enabled.

content/browser/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("//build/config/ui.gni")
 import("//media/media_options.gni")
 import("//ppapi/features/features.gni")
 import("//printing/features/features.gni")
 import("//third_party/WebKit/public/public_features.gni")
@@ skipping 1482 matching lines @@
       "webrtc/webrtc_internals_ui_observer.h",
     ]
 
     deps += [
       "//jingle:jingle_glue",
       "//third_party/libjingle/webrtc:libjingle_webrtc",
       "//third_party/webrtc/base:rtc_base",
       "//third_party/webrtc/media:rtc_media_base",
       "//third_party/webrtc/modules/desktop_capture:primitives",
     ]
-
-    if (is_linux || is_mac || is_win) {
-      sources += [
-        "media/capture/desktop_capture_device.cc",
-        "media/capture/desktop_capture_device.h",
-      ]
-      deps += [ "//third_party/webrtc/modules/desktop_capture" ]
-    }
   }
 
   # Desktop screen capture implementations that are not dependent on WebRTC.

[miu, 2017/01/10 23:58:15]

This comment needs a little adjusting now. Maybe it could be just:

  # Desktop screen capture implementations, conditionally built depending on the
available implementations for each platform.

[byungchul, 2017/01/11 17:13:04]

Done.

   if (is_linux || is_mac || is_win) {
     defines += [ "ENABLE_SCREEN_CAPTURE=1" ]
     sources += [
       "media/capture/cursor_renderer.cc",
       "media/capture/cursor_renderer.h",
       "media/capture/web_contents_video_capture_device.cc",
       "media/capture/web_contents_video_capture_device.h",
       "media/capture/window_activity_tracker.cc",
       "media/capture/window_activity_tracker.h",
     ]
@@ skipping 10 matching lines @@
       ]
     }
     if (is_mac) {
       sources += [
         "media/capture/cursor_renderer_mac.h",
         "media/capture/cursor_renderer_mac.mm",
         "media/capture/window_activity_tracker_mac.h",
         "media/capture/window_activity_tracker_mac.mm",
       ]
     }
+    if (enable_webrtc) {
+      sources += [
+        "media/capture/desktop_capture_device.cc",
+        "media/capture/desktop_capture_device.h",
+      ]
+      deps += [ "//third_party/webrtc/modules/desktop_capture" ]
+    }
   }
 
   if (is_win) {
     sources -= [ "device_sensors/data_fetcher_shared_memory_default.cc" ]
     defines += [
       # This prevents the inclusion of atlhost.h which paired
       # with the windows 8 sdk it does the wrong thing.
       "__ATLHOST_H__",
     ]
     deps += [
@@ skipping 452 matching lines @@
   if (!is_component_build) {
     public_deps = [
       ":browser",
     ]
   } else {
     public_deps = [
       "//third_party/leveldatabase",
     ]
   }
 }