Reduce composited smooth scroll latency by a frame (also fixes latency UMAs).

content/test/BUILD.gn

 # Copyright 2014 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/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
@@ skipping 652 matching lines @@
     "../browser/net_info_browsertest.cc",
     "../browser/payments/payment_app_browsertest.cc",
     "../browser/pointer_lock_browsertest.cc",
     "../browser/pointer_lock_browsertest.h",
     "../browser/pointer_lock_browsertest_mac.mm",
     "../browser/presentation/presentation_browsertest.cc",
     "../browser/renderer_host/input/composited_scrolling_browsertest.cc",
     "../browser/renderer_host/input/interaction_mq_dynamic_browsertest.cc",
     "../browser/renderer_host/input/main_thread_event_queue_browsertest.cc",
     "../browser/renderer_host/input/non_blocking_event_browsertest.cc",
+    "../browser/renderer_host/input/scroll_latency_browsertest.cc",
     "../browser/renderer_host/input/touch_action_browsertest.cc",
     "../browser/renderer_host/input/touch_input_browsertest.cc",
     "../browser/renderer_host/input/touch_selection_controller_client_aura_browsertest.cc",
     "../browser/renderer_host/media/video_capture_browsertest.cc",
     "../browser/renderer_host/render_process_host_browsertest.cc",
     "../browser/renderer_host/render_view_host_browsertest.cc",
     "../browser/renderer_host/render_widget_host_view_browsertest.cc",
     "../browser/resource_loading_browsertest.cc",
     "../browser/screen_orientation/screen_orientation_browsertest.cc",
     "../browser/security_exploit_browsertest.cc",
@@ skipping 1153 matching lines @@
   if (is_android) {
     deps += [ "//testing/android/native_test:native_test_native_code" ]
   }
 }
 
 group("fuzzers") {
   deps = [
     "//content/test/fuzzer",
   ]
 }