Add BUILD.gn for benchmarks (flutter#75)

Author: GaryQian

build/secondary/testing/benchmark/BUILD.gn

@@ -0,0 +1,55 @@
+# Copyright 2017 Google, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+static_library("benchmark") {
+  defines = [ "HAVE_STD_REGEX" ]
+
+  include_dirs = [
+    "//third_party/benchmark/include",
+  ]
+
+  sources = [
+    "//third_party/benchmark/src/arraysize.h",
+    "//third_party/benchmark/src/benchmark.cc",
+    "//third_party/benchmark/src/benchmark_api_internal.h",
+    "//third_party/benchmark/src/benchmark_register.cc",
+    "//third_party/benchmark/src/check.h",
+    "//third_party/benchmark/src/colorprint.cc",
+    "//third_party/benchmark/src/colorprint.h",
+    "//third_party/benchmark/src/commandlineflags.cc",
+    "//third_party/benchmark/src/commandlineflags.h",
+    "//third_party/benchmark/src/complexity.cc",
+    "//third_party/benchmark/src/complexity.h",
+    "//third_party/benchmark/src/console_reporter.cc",
+    "//third_party/benchmark/src/counter.cc",
+    "//third_party/benchmark/src/counter.h",
+    "//third_party/benchmark/src/csv_reporter.cc",
+    "//third_party/benchmark/src/cycleclock.h",
+    "//third_party/benchmark/src/internal_macros.h",
+    "//third_party/benchmark/src/json_reporter.cc",
+    "//third_party/benchmark/src/log.h",
+    "//third_party/benchmark/src/mutex.h",
+    "//third_party/benchmark/src/re.h",
+    "//third_party/benchmark/src/reporter.cc",
+    "//third_party/benchmark/src/sleep.cc",
+    "//third_party/benchmark/src/sleep.h",
+    "//third_party/benchmark/src/stat.h",
+    "//third_party/benchmark/src/string_util.cc",
+    "//third_party/benchmark/src/string_util.h",
+    "//third_party/benchmark/src/sysinfo.cc",
+    "//third_party/benchmark/src/sysinfo.h",
+    "//third_party/benchmark/src/timers.cc",
+    "//third_party/benchmark/src/timers.h",
+  ]
+}