Add CSSTiming to collect aggregate PLT-level stats about CSS.

third_party/WebKit/Source/core/css/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("//third_party/WebKit/Source/core/core.gni")
 
 blink_core_sources("css") {
   split_count = 5
   sources = [
     "ActiveStyleSheets.cpp",
@@ skipping 115 matching lines @@
     "CSSStyleDeclaration.cpp",
     "CSSStyleDeclaration.h",
     "CSSStyleRule.cpp",
     "CSSStyleRule.h",
     "CSSStyleSheet.cpp",
     "CSSStyleSheet.h",
     "CSSSupportsRule.cpp",
     "CSSSupportsRule.h",
     "CSSSyntaxDescriptor.cpp",
     "CSSSyntaxDescriptor.h",
+    "CSSTiming.cpp",
+    "CSSTiming.h",
     "CSSTimingFunctionValue.cpp",
     "CSSTimingFunctionValue.h",
     "CSSToLengthConversionData.cpp",
     "CSSToLengthConversionData.h",
     "CSSURIValue.cpp",
     "CSSURIValue.h",
     "CSSUnicodeRangeValue.cpp",
     "CSSUnicodeRangeValue.h",
     "CSSUnsetValue.cpp",
     "CSSUnsetValue.h",
@@ skipping 237 matching lines @@
     "resolver/TransformBuilder.h",
     "resolver/ViewportStyleResolver.cpp",
     "resolver/ViewportStyleResolver.h",
   ]
 
   configs += [
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 }