Roll jsoncpp, drop dependency on Chromium overrides.

DEPS

 use_relative_paths = True
 
 # Dependencies on outside packages.
 #
 deps = {
   "common": "https://skia.googlesource.com/common.git@a7b0283c39dfdf5553859eb9790c970bb52cda47",
 
-  # DEPS using https://chromium.googlesource.com are pulled from chromium @ r205199
-  # (see https://chromium.googlesource.com/chromium/chromium/+/c59bfa8ef877f45bfa859669053859857af1d279)
   "third_party/externals/angle2" : "https://chromium.googlesource.com/angle/angle.git@23a8a433529d9db23882c702a29d5e594841563d",
   "third_party/externals/freetype" : "https://skia.googlesource.com/third_party/freetype2.git@VER-2-5-0-1",
   "third_party/externals/gyp" : "https://chromium.googlesource.com/external/gyp.git@3917682a16d5c19ff3576a8be0ffdb3a332954b1",
   "third_party/externals/libjpeg" : "https://chromium.googlesource.com/chromium/deps/libjpeg_turbo.git@82ce8a6d4ebe12a177c0c3597192f2b4f09e81c3",
-  "third_party/externals/jsoncpp" : "https://chromium.googlesource.com/external/jsoncpp/jsoncpp.git@ab1e40f3bce061ea6f9bdc60351d6cde2a4f872b",
-  # Move to a webp version newer than 0.3.0 to pickup NEON fix for iOS
-  "third_party/externals/jsoncpp-chromium" : "https://chromium.googlesource.com/chromium/src/third_party/jsoncpp.git@41239939c0c60481f34887d52c038facf05f5533",
+  "third_party/externals/jsoncpp" : "https://chromium.googlesource.com/external/jsoncpp/jsoncpp.git@1afff032c83e26ddf7f2776e8b43de5ad666c1fa",
   "third_party/externals/libwebp" : "https://chromium.googlesource.com/webm/libwebp.git@3fe91635df8734b23f3c1b9d1f0c4fa8cfaf4e39",
-  # "third_party/externals/v8" : "git://github.com/v8/v8.git@d15b0f0f2099dbd72867f3df70e9aaf5b8afbd2c",
   "third_party/externals/nanomsg": "git://github.com/nanomsg/nanomsg.git@0.4-beta",
 }
 
 recursedeps = [
   "common",
 ]
 
 deps_os = {
   "android": {
     "platform_tools/android/third_party/externals/expat" : "https://android.googlesource.com/platform/external/expat.git@android-4.2.2_r1.2",
@@ skipping 20 matching lines @@
   }
 }
 
 #hooks = [
 #  {
 #    # A change to a .gyp, .gypi, or to GYP itself should run the generator.
 #    "pattern": ".",
 #    "action": ["python", "trunk/gyp_skia"],
 #  },
 #]