DesktopCaptureDevice is available when webrtc is enabled.

content/browser/BUILD.gn

Index: content/browser/BUILD.gn
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index a08452be25868cc8a74dd6134b23452637d2b65a..40ebbce24dcb14139a4ba35d7fa7a0a63e1ac265 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -1500,14 +1500,6 @@ source_set("browser") {
       "//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.

@@ -1541,6 +1533,13 @@ source_set("browser") {
         "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) {