Update DEPS and GYP to use the copy of Android in platform_tools.

DEPS

 use_relative_paths = True
 
 # Dependencies on outside packages, as needed for developers/bots that use
 # "gclient" instead of raw SVN access.
 #
 # For now, this must be maintained in parallel with "SVN externals"
 # dependencies for developers who use raw SVN instead of "gclient".
 # See third_party/externals/README
 #
 deps = {
   "third_party/externals/angle" : "http://angleproject.googlecode.com/svn/trunk@1268",
   "third_party/externals/cityhash" : "http://cityhash.googlecode.com/svn/trunk@11",
   "third_party/externals/freetype" : "https://android.googlesource.com/platform/external/freetype.git",
   "third_party/externals/gyp" : "http://gyp.googlecode.com/svn/trunk@1563",
   "third_party/externals/libjpeg" : "http://src.chromium.org/svn/trunk/src/third_party/libjpeg@125399",
   "third_party/externals/jsoncpp" : "http://jsoncpp.svn.sourceforge.net/svnroot/jsoncpp/trunk/jsoncpp@248",
   "third_party/externals/jsoncpp-chromium" : "http://src.chromium.org/svn/trunk/src/third_party/jsoncpp@125399",
   "third_party/externals/libwebp" : "http://src.chromium.org/svn/trunk/src/third_party/libwebp@186718",
 }
 
+deps_os = {
+  "android": {
+    "platform_tools/android/third_party/externals/expat" : "https://android.googlesource.com/platform/external/expat.git",
+    "platform_tools/android/third_party/externals/gif" : "https://android.googlesource.com/platform/external/giflib.git",
+    "platform_tools/android/third_party/externals/png" : "https://android.googlesource.com/platform/external/libpng.git",
+    "platform_tools/android/third_party/externals/jpeg" : "https://android.googlesource.com/platform/external/jpeg.git",
+  },
+}
+
 #hooks = [
 #  {
 #    # A change to a .gyp, .gypi, or to GYP itself should run the generator.
 #    "pattern": ".",
 #    "action": ["python", "trunk/gyp_skia"],
 #  },
 #]