Add performance test skeleton.

test/perf-tests/perf-tests.gyp

Index: test/perf-tests/perf-tests.gyp
diff --git a/test/base-unittests/base-unittests.gyp b/test/perf-tests/perf-tests.gyp
similarity index 71%
copy from test/base-unittests/base-unittests.gyp
copy to test/perf-tests/perf-tests.gyp
index 6b69f1c9842e5811448b8eeb80fb8144deb0f233..5cc5f7da312aba51741fa55d98a1e9b4ef4808ae 100644
--- a/test/base-unittests/base-unittests.gyp
+++ b/test/perf-tests/perf-tests.gyp
@@ -9,7 +9,7 @@
   'includes': ['../../build/toolchain.gypi', '../../build/features.gypi'],
   'targets': [
     {
-      'target_name': 'base-unittests',
+      'target_name': 'perf-tests',
       'type': 'executable',
       'dependencies': [
         '../../testing/gtest.gyp:gtest',
@@ -20,14 +20,7 @@
         '../..',
       ],
       'sources': [  ### gcmole(all) ###
-        'bits-unittest.cc',
-        'cpu-unittest.cc',
-        'platform/condition-variable-unittest.cc',
-        'platform/mutex-unittest.cc',
-        'platform/platform-unittest.cc',
-        'platform/semaphore-unittest.cc',
-        'platform/time-unittest.cc',
-        'utils/random-number-generator-unittest.cc',
+        'infra-test.cc',
       ],
       'conditions': [
         ['os_posix == 1', {