diff --git a/gyp_packager.py b/gyp_packager.py
index 6559e2b078..89320eba6b 100755
--- a/gyp_packager.py
+++ b/gyp_packager.py
@@ -14,12 +14,12 @@
 # 1. Setup gyp: ./gyp_packager.py
 #
 # clang is not enabled by default, which can be enabled by overriding
-# GYP_DEFINE environment variable, i.e. "GYP_DEFINES='clang=1
-# use_openssl=1' ./gyp_packager.py".
+# GYP_DEFINE environment variable, i.e.
+# "GYP_DEFINES='clang=1' ./gyp_packager.py".
 #
 # Ninja is the default build system. User can also change to make by
-# overriding GYP_GENERATORS to make, i.e. "GYP_GENERATORS='make'
-# ./gyp_packager.py".
+# overriding GYP_GENERATORS to make, i.e.
+# "GYP_GENERATORS='make' ./gyp_packager.py".
 #
 # 2. The first step generates the make files but does not start the
 # build process. Ninja is the default build system. Refer to Ninja
@@ -59,9 +59,16 @@ if __name__ == '__main__':
   # Gyp should run from current directory.
   args.append('--depth=.')
 
-  # Set GYP_DEFINES if it is not explicitly set yet.
-  if not os.environ.get('GYP_DEFINES'):
-    os.environ['GYP_DEFINES'] = 'use_openssl=1'
+  # Set these default GYP_DEFINES if user does not set the value explicitly.
+  _DEFAULT_DEFINES = {"test_isolation_mode" : "noop", "use_glib" : 0,
+                      "use_openssl" : 1, "use_x11" : 0}
+
+  gyp_defines = (os.environ['GYP_DEFINES'] if os.environ.get('GYP_DEFINES')
+                 else "")
+  for key in _DEFAULT_DEFINES:
+    if key not in gyp_defines:
+      gyp_defines += " {}={}".format(key, _DEFAULT_DEFINES[key])
+  os.environ['GYP_DEFINES'] = gyp_defines.strip()
 
   # There shouldn't be a circular dependency relationship between .gyp files,
   # but in Chromium's .gyp files, on non-Mac platforms, circular relationships
diff --git a/media/event/media_event.gyp b/media/event/media_event.gyp
index a620d3a89d..cbd033f1ec 100644
--- a/media/event/media_event.gyp
+++ b/media/event/media_event.gyp
@@ -38,9 +38,9 @@
       ],
       'dependencies': [
         '../../base/base.gyp:base',
-        '../../base/base.gyp:run_all_unittests',
         '../../mpd/mpd.gyp:media_info_proto',
         '../../testing/gtest.gyp:gtest',
+        '../../testing/gtest.gyp:gtest_main',
         # Depends on full protobuf to read/write with TextFormat.
         '../../third_party/protobuf/protobuf.gyp:protobuf_full_do_not_use',
         '../file/file.gyp:file',
diff --git a/media/test/media_test.gyp b/media/test/media_test.gyp
index 20e1ed6e79..f1ad4254a2 100644
--- a/media/test/media_test.gyp
+++ b/media/test/media_test.gyp
@@ -12,16 +12,25 @@
   },
   'targets': [
     {
-      'target_name': 'media_test_support',
+      'target_name': 'run_all_unittests',
       'type': '<(component)',
       'sources': [
         'run_tests_with_atexit_manager.cc',
+      ],
+      'dependencies': [
+        '../../testing/gtest.gyp:gtest',
+      ],
+    },
+    {
+      'target_name': 'media_test_support',
+      'type': '<(component)',
+      'sources': [
         'test_data_util.cc',
         'test_data_util.h',
       ],
       'dependencies': [
         '../../base/base.gyp:base',
-        '../../testing/gtest.gyp:gtest',
+        'run_all_unittests',
       ],
     },
   ],
diff --git a/mpd/mpd.gyp b/mpd/mpd.gyp
index b9a35bd7b1..06fb119356 100644
--- a/mpd/mpd.gyp
+++ b/mpd/mpd.gyp
@@ -68,8 +68,8 @@
       ],
       'dependencies': [
         '../base/base.gyp:base',
-        '../base/base.gyp:run_all_unittests',
         '../media/file/file.gyp:file',
+        '../media/test/media_test.gyp:run_all_unittests',
         '../testing/gtest.gyp:gtest',
         'mpd_builder',
         'mpd_util',