third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/README.chromium

 Name: Protocol Buffers
 Short Name: protobuf
 URL: https://github.com/google/protobuf
 License: BSD
 License File: LICENSE
-Version: 3.0.0-beta-3
-Revision: 3470b6895aa659b7559ed678e029a5338e535f14
+Version: 3.1.0
+Revision: 83d681ee2caef1feb009656417830f846382d8ba
 Security Critical: yes
 
 Steps used to create the current version:
 1. Pull the release from https://github.com/google/protobuf/releases
-2. Add build files (BUILD.gn, proto_library.gni, protobuf.gyp,
-   protobuf_lite.gypi, protobuf_nacl.gyp).
+2. Add build files (BUILD.gn, proto_library.gni).
 
    Be sure to update the list of source files, as additional .cc files and
    headers might have been added -- you need to find the transitive closure of
    include files required by targets.
 
    Other things to care about are defines required by protobuf on various
    platforms, warnings generated by compilers, and new dependencies introduced.
 3. Get open-source library six.py from https://pypi.python.org/pypi/six/ and add
    it to protobuf/third_party/six/six.py.
 4. Apply patches in patches/ (see the description below):
 
    $ for patch in patches/*; do patch -s -p1 < $patch; done
 
    For future releases, it will be worth looking into which patches still need
-   to be applied.
+   to be applied. In case of conflict, update those patches accordingly and save
+   them back in place (i.e. in patches directory).
 5. Generate descriptor_pb2.py using something like the following steps. Make
    sure you've regenerated your buildfiles and will build protoc from the
    newly-modified sources above.
 
    $ cd $SRC_DIR
    $ ninja -C out/Debug protoc
    $ cd third_party/protobuf/src
    $ ../../../out/Debug/protoc --python_out=../python google/protobuf/descriptor.proto
 
 6. Add an __init__.py to protobuf/ that adds third_party/six/ to Python path.
 7. Update README.chromium.
 
 Description of the patches:
 
 - 0003-remove-static-initializers.patch
 
   This patch removes all static initializers from Chromium. The change in Status
   class is not completely compatible with upstream, but it's compatible enough
   to work in Chromium, which doesn't use this functionality yet. The work on
   upstreaming the removal of static initializers is in progress:
   https://github.com/google/protobuf/issues/1404
 
 - 0004-fix-integer-types-and-shared-library-exports.patch
 
   This patch makes protobuf int64 to be int64_t (as opposed to long long in
   upstream), and similarly for other integer types. It also allows exporting
   protobuf symbols in Linux .so libraries, so that protobuf can be built as a
   component (see http://crrev.com/179806).
 
-- 0005-fix-include-js-generator.protobuf
-
-  During merge with internal branch, the <> in one of the #includes were
-  accidentally replaced with "", which results in a failure in checkdeps.
-
-  Fixed in https://github.com/google/protobuf/pull/1547.
-
 - 0007-uninline_googleonce.patch
 - 0008-uninline_get_empty_string.patch
 - 0009-uninline-arenastring.patch
 - 0010-uninline-generated-code.patch
 
   These patches uninline some functions, resulting in a significant reduction
   (somewhere between 500 KB and 1 MB) of binary size.
-
-- 0011-libprotobuf_export.patch
-
-  During merge with internal branch, the dll export attribute was accidentally
-  removed in C++11 mode.
-
-  Fixed in https://github.com/google/protobuf/pull/1549