[vr] Add a frame rate counter for the vr UI

chrome/browser/android/vr_shell/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/rules.gni")
 import("//chrome/common/features.gni")
 import("//device/vr/features.gni")
 import("//testing/test.gni")
 
 assert(enable_vr)
 
 if (current_cpu == "arm" || current_cpu == "arm64") {
   static_library("vr_common") {
     defines = []
 
     sources = [
       "android_ui_gesture_target.cc",
       "android_ui_gesture_target.h",
       "animation.cc",
       "animation.h",
       "easing.cc",
       "easing.h",
+      "fps_meter.cc",
+      "fps_meter.h",
       "gltf_asset.cc",
       "gltf_asset.h",
       "gltf_parser.cc",
       "gltf_parser.h",
       "mailbox_to_surface_bridge.cc",
       "mailbox_to_surface_bridge.h",
       "non_presenting_gvr_delegate.cc",
       "non_presenting_gvr_delegate.h",
       "ui_elements.cc",
       "ui_elements.h",
@@ skipping 69 matching lines @@
       "//chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java",
       "//chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java",
     ]
     jni_package = "vr_shell"
   }
 }
 
 if (enable_vr) {
   test("vr_shell_unittests") {
     sources = [
+      "fps_meter_unittest.cc",
       "gltf_parser_unittest.cc",
       "test/paths.cc",
       "test/paths.h",
       "ui_elements_unittest.cc",
       "ui_scene_unittest.cc",
     ]
 
     deps = [
       ":vr_common",
       "//base/test:run_all_unittests",
       "//base/test:test_support",
       "//chrome/browser",
       "//testing/gtest",
       "//third_party/WebKit/public:blink",
       "//ui/gfx/geometry",
     ]
 
     # Ensure libgvr static library appears before gcc library in linking order.
     # See https://crbug.com/704305 for details.
-    libs = [
-      "//third_party/gvr-android-sdk/libgvr_shim_static_${current_cpu}.a",
-    ]
+    libs =
+        [ "//third_party/gvr-android-sdk/libgvr_shim_static_${current_cpu}.a" ]
 
     data = [
       "test/data/sample_inline.gltf",
       "test/data/sample_external.gltf",
       "test/data/sample.bin",
     ]
   }
 }