Add Linux and MacOS support to perf_test_runner.py

This patch enables perf_test_runner.py to run on Linux and MacOS.

BUG=angleproject:2029

Change-Id: Ia7176a3f5fed0245ab72d5def1199623c4fb4fe2
Reviewed-on: https://chromium-review.googlesource.com/497648
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/scripts/perf_test_runner.py b/scripts/perf_test_runner.py
index 87e5b5f..3e896b3 100644
--- a/scripts/perf_test_runner.py
+++ b/scripts/perf_test_runner.py
@@ -28,8 +28,9 @@
 ]
 metric = 'score'
 
-# TODO(jmadill): Linux binaries
-binary_name = 'angle_perftests.exe'
+binary_name = 'angle_perftests'
+if sys.platform == 'win32':
+    binary_name += '.exe'
 
 scores = []
 
@@ -83,10 +84,13 @@
 perftests_path = newest_binary
 
 if perftests_path == None or not os.path.exists(perftests_path):
-    print("Cannot find Release angle_perftests.exe!")
+    print('Cannot find Release %s!' % binary_name)
     sys.exit(1)
 
-test_name = "DrawCallPerfBenchmark.Run/d3d11_null"
+if sys.platform == 'win32':
+    test_name = 'DrawCallPerfBenchmark.Run/d3d11_null'
+else:
+    test_name = 'DrawCallPerfBenchmark.Run/gl'
 
 if len(sys.argv) >= 2:
     test_name = sys.argv[1]