Refactor webrtc/modules/desktop_capture for GN check

This moves some GN check configurations out of .gn to individual
targets.

The now checked target is:
"//webrtc/modules/desktop_capture/*"

BUG=webrtc:6828
NOTRY=True

Review-Url: https://codereview.webrtc.org/2593713002
Cr-Commit-Position: refs/heads/master@{#15725}
diff --git a/.gn b/.gn
index a0fd50a..7849e32 100644
--- a/.gn
+++ b/.gn
@@ -28,6 +28,7 @@
   "//webrtc/modules/audio_device/*",
   "//webrtc/modules/audio_mixer/*",
   "//webrtc/modules/audio_processing/*",
+  "//webrtc/modules/desktop_capture/*",
   "//webrtc/modules/video_capture/*",
   "//webrtc/modules/video_coding/*",
   "//webrtc/stats:rtc_stats",
diff --git a/webrtc/modules/desktop_capture/BUILD.gn b/webrtc/modules/desktop_capture/BUILD.gn
index 5d27994..6a10c34 100644
--- a/webrtc/modules/desktop_capture/BUILD.gn
+++ b/webrtc/modules/desktop_capture/BUILD.gn
@@ -22,10 +22,14 @@
     "desktop_region.h",
     "shared_desktop_frame.cc",
     "shared_desktop_frame.h",
+    "shared_memory.cc",
+    "shared_memory.h",
   ]
 
   deps = [
+    "../..:webrtc_common",
     "../../base:rtc_base",  # TODO(kjellander): Cleanup in bugs.webrtc.org/3806.
+    "../../system_wrappers:system_wrappers",
   ]
 }
 
@@ -41,6 +45,10 @@
       "rgba_color.cc",
       "rgba_color.h",
     ]
+    deps = [
+      ":primitives",
+      "../..:webrtc_common",
+    ]
   }
 
   source_set("screen_drawer") {
@@ -57,6 +65,11 @@
       "screen_drawer_mac.cc",
       "screen_drawer_win.cc",
     ]
+    deps = [
+      ":primitives",
+      "../../base:rtc_base_approved",
+      "../../system_wrappers:system_wrappers",
+    ]
   }
 
   source_set("desktop_capture_mock") {
@@ -75,7 +88,11 @@
       "fake_desktop_capturer.h",
       "mock_desktop_capturer_callback.cc",
       "mock_desktop_capturer_callback.h",
-      "screen_capturer_mock_objects.h",
+    ]
+    deps = [
+      ":primitives",
+      "../../base:rtc_base_approved",
+      "../../test:test_support",
     ]
   }
 }
@@ -121,8 +138,6 @@
     "screen_capturer_helper.h",
     "screen_capturer_mac.mm",
     "screen_capturer_win.cc",
-    "shared_memory.cc",
-    "shared_memory.h",
     "win/cursor.cc",
     "win/cursor.h",
     "win/d3d_device.cc",
@@ -198,6 +213,7 @@
 
   deps = [
     ":primitives",
+    "../..:webrtc_common",
     "../../base:rtc_base",  # TODO(kjellander): Cleanup in bugs.webrtc.org/3806.
     "../../system_wrappers",
     "//third_party/libyuv",