Add initial BUILD.gn in platform/wtf/, and move first a few files there.

third_party/WebKit/Source/wtf/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.
 
 assert(!is_ios)
 
 import("//testing/test.gni")
 import("//third_party/WebKit/Source/config.gni")
 
 visibility = [
   "//mojo/public/cpp/bindings/*",
   "//third_party/WebKit/*",
 ]
 
 config("wtf_config") {
-  if (is_win) {
-    defines = [
-      "__STD_C",
-      "_CRT_SECURE_NO_DEPRECATE",
-      "_SCL_SECURE_NO_DEPRECATE",
-    ]
-    include_dirs = [ "os-win32" ]
-
-    cflags = [
-      # Don't complain about calling specific versions of templatized
-      # functions (e.g. in RefPtrHashMap.h).
-      "/wd4344",
-
-      # dtoa, icu, etc. like doing assignment within conditional.
-      "/wd4706",
-    ]
-
-    if (is_component_build) {
-      # Chromium windows multi-dll build enables C++ exceptions and this causes
-      # wtf to generate 4291 warning due to operator new/delete
-      # implementations. Disable the warning for chromium windows multi-dll
-      # build.
-      cflags += [ "/wd4291" ]
-    }
-  }
+  configs = [ "//third_party/WebKit/Source/platform/wtf:wtf_config" ]
 }
 
 component("wtf") {
   sources = [
     "ASCIICType.cpp",
     "ASCIICType.h",
     "AddressSanitizer.h",
     "Alignment.h",
     "Allocator.h",
     "Assertions.cpp",
     "Assertions.h",
     "Atomics.h",
     "AutoReset.h",
     "BitVector.cpp",
     "BitVector.h",
     "BitwiseOperations.h",
     "BloomFilter.h",
     "ByteOrder.h",
     "ByteSwap.h",
     "CPU.h",
     "CheckedNumeric.h",
     "Compiler.h",
     "ConditionalDestructor.h",
     "ContainerAnnotations.h",
-    "CryptographicallyRandomNumber.cpp",
     "CryptographicallyRandomNumber.h",
     "CurrentTime.cpp",
     "CurrentTime.h",
     "DataLog.cpp",
     "DataLog.h",
     "DateMath.cpp",
     "DateMath.h",
     "Deque.h",
     "DoublyLinkedList.h",
     "DynamicAnnotations.cpp",
@@ skipping 175 matching lines @@
   public_configs = [
     ":wtf_config",
 
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
     "//third_party/WebKit/Source:features",
   ]
 
   public_deps = [
     "//base",
+    "//third_party/WebKit/Source/platform/wtf:platform_wtf",
     "//third_party/icu",
   ]
 
   if (is_win) {
     sources -= [ "ThreadingPthreads.cpp" ]
 
     cflags = [ "/wd4068" ]  # Unknown pragma.
   } else {
     # Non-Windows.
     sources -= [
@@ skipping 84 matching lines @@
   ]
 
   deps = [
     ":wtf",
     "//base",
     "//base/test:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }