Update isolate files for swarming tests

Xvfb is needed for the screen capture tests in modules_unittests,
which also brings in xdisplaycheck used by testing/xvfb.py.

libjingle_media_unittest was missing a resource video in the .isolate
file.

BUG=chromium:497757
R=stip@chromium.org

Review URL: https://codereview.webrtc.org/1415603005 .

Cr-Commit-Position: refs/heads/master@{#10365}
diff --git a/webrtc/modules/modules_unittests.isolate b/webrtc/modules/modules_unittests.isolate
index bc6437f..5035f6e 100644
--- a/webrtc/modules/modules_unittests.isolate
+++ b/webrtc/modules/modules_unittests.isolate
@@ -129,7 +129,7 @@
         ],
       },
     }],
-    ['OS=="linux" or OS=="mac" or OS=="win"', {
+    ['(OS=="linux" or OS=="mac" or OS=="win") and use_x11==0', {
       'variables': {
         'command': [
           '<(DEPTH)/testing/test_env.py',
@@ -142,5 +142,22 @@
         ],
       },
     }],
+    ['(OS=="linux" or OS=="mac" or OS=="win") and use_x11==1', {
+      'variables': {
+        'command': [
+          '<(DEPTH)/testing/xvfb.py',
+          '<(PRODUCT_DIR)',
+          '<(DEPTH)/testing/test_env.py',
+          '<(PRODUCT_DIR)/modules_unittests<(EXECUTABLE_SUFFIX)',
+        ],
+        'files': [
+          '<(DEPTH)/DEPS',
+          '<(DEPTH)/testing/test_env.py',
+          '<(DEPTH)/testing/xvfb.py',
+          '<(PRODUCT_DIR)/modules_unittests<(EXECUTABLE_SUFFIX)',
+          '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
+        ],
+      },
+    }],
   ],
 }