Add gpu_perftests to perfbots.

gpu/perftests/run_all_tests.cc

Index: gpu/perftests/run_all_tests.cc
diff --git a/gpu/perftests/run_all_tests.cc b/gpu/perftests/run_all_tests.cc
index ed0df882f742d085b18999e96af5ee50ea3a95bc..60a6b03af219f66f4640940664a25f9ae88ca98e 100644
--- a/gpu/perftests/run_all_tests.cc
+++ b/gpu/perftests/run_all_tests.cc
@@ -9,7 +9,10 @@
 int main(int argc, char** argv) {
   base::TestSuite test_suite(argc, argv);
 
+  // Always run the perf tests serially, to avoid distorting
+  // perf measurements with randomness resulting from running
+  // in parallel.
   const auto& run_test_suite =
       base::Bind(&base::TestSuite::Run, base::Unretained(&test_suite));
-  return base::LaunchUnitTests(argc, argv, run_test_suite);
+  return base::LaunchUnitTestsSerially(argc, argv, run_test_suite);
 }