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

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 0cdc5fb51be2a78214afa9debbd0915525906b12..2a3719904bc0e11f53535ed7c84073c1867bc2bb 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -84,6 +84,8 @@ group("root") {
     "//ui/surface",
     "//url",
     "//v8:mksnapshot",
+    "//webkit/browser:storage",
+    "//webkit/child",
   ]
 
   if (is_linux) {
@@ -109,6 +111,10 @@ group("root") {
       "//third_party/WebKit/Source/wtf",  # TODO(brettw) re-enable for Android.
       "//tools/gn",
 
+      # Not tested on Android yet:
+      "//webkit/browser:storage",
+      "//webkit/child",
+
       # This stuff all depends on ui/surface which requires some .class jni
       # generators (ui/gl/gl.gyp:surface_jni_headers).
       "//ui/gl",