Updating android_protobuf to L-preview branch

Adding support for the optional_field_style=reftypes flag.
This is needed for the invalidation client which expects
"boxed" types (e.g., Boolean rather than boolean) for
primitive fields, and depends on null comparisons to
determine whether or not a field is set.

BUG=377891,411282
R=nyquist@chromium.org

Review URL: https://codereview.chromium.org/549543002

Patch from Colin Meek <meek@chromium.org>.

Cr-Commit-Position: refs/heads/master@{#293583}

DEPS

@@ -466,7 +466,7 @@ deps_os = {
   },
   'android': {
     'src/third_party/android_protobuf/src':
-     Var('chromium_git') + '/external/android_protobuf.git' + '@' + '48ee66d295979372ed0234cefda42385daae8312',
+     Var('chromium_git') + '/external/android_protobuf.git' + '@' + '94f522f907e3f34f70d9e7816b947e62fddbb267',
 
     'src/third_party/android_tools':
      Var('chromium_git') + '/android_tools.git' + '@' + '7fc902d157a9aed7a2b68adc9c69181b3a43cd58',

third_party/android_protobuf/OWNERS

 cjhopman@chromium.org
 nyquist@chromium.org
+meek@chromium.org
\ No newline at end of file

third_party/android_protobuf/README.chromium

@@ -2,7 +2,7 @@ Name: Protocol Buffers - Google's data interchange format
 Short Name: protobuf
 URL: https://android.googlesource.com/platform/external/protobuf.git
 Version: 2.2.0a
-Revision: Android 4.4.4 Release 2.0.1
+Revision: L-preview
 License: BSD
 License File: src/COPYING.txt
 Security Critical: no