Add some src/webkit build files to the GN build.

webkit/child/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.
+
+component("child") {
+  output_name = "webkit_child"
+  sources = [
+    "multipart_response_delegate.cc",
+    "multipart_response_delegate.h",
+    "resource_loader_bridge.cc",
+    "resource_loader_bridge.h",
+    "webkit_child_export.h",
+    "weburlresponse_extradata_impl.cc",
+    "weburlresponse_extradata_impl.h",
+  ]
+
+  defines = [ "WEBKIT_CHILD_IMPLEMENTATION" ]
+  include_dirs = [
+    # For JNI generated header.
+    "$root_gen_dir/webkit",
+  ]
+
+  configs += [ "//build/config/compiler:wexit_time_destructors" ]
+  if (is_win) {
+    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+    cflags += [ "/wd4267" ]
+  }
+
+  if (is_mac) {
+    libs = [ "QuartzCore.framework" ]
+  }
+  if (is_android) {
+    #deps += [ ":overscroller_jni_headers" ]  TODO(GYP)
+  }
+
+  deps = [
+    "//base",
+    "//base:i18n",
+    "//base/third_party/dynamic_annotations",
+    "//net",
+    "//skia",
+    #"//third_party/WebKit/public:blink",  TODO(GYP)
+    "//ui/gfx",
+    "//ui/gfx/geometry",
+    "//ui/native_theme",
+    "//url",
+    #"//v8",  TODO(GYP)
+    "//webkit/common",
+  ]
+}
+
+#TODO(GYP)
+#'target_name': 'overscroller_jni_headers',
+#'type': 'none',
+#'variables': {
+#  'jni_gen_package': 'webkit',
+#  'input_java_class': 'android/widget/OverScroller.class',
+#},
+#'includes': [ '../../build/jar_file_jni_generator.gypi' ],
+