Update //third_party/protobuf to version 3.

third_party/protobuf/.gitignore

Index: third_party/protobuf/.gitignore
diff --git a/third_party/protobuf/.gitignore b/third_party/protobuf/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..19e5212986b78060f1c793d1f9556ff417c4f8ac
--- /dev/null
+++ b/third_party/protobuf/.gitignore
@@ -0,0 +1,114 @@
+# autogen.sh-generated files
+Makefile.in
+src/Makefile.in
+config.guess
+config.h.in
+config.sub
+configure
+depcomp
+install-sh
+ltmain.sh
+missing
+
+aclocal.m4
+m4/libtool.m4
+m4/ltoptions.m4
+m4/ltsugar.m4
+m4/ltversion.m4
+m4/lt~obsolete.m4
+autom4te.cache
+
+# downloaded files
+gmock
+
+# in-tree configure-generated files
+Makefile
+src/Makefile
+/config.h
+config.log
+config.status
+
+libtool
+protobuf-lite.pc
+protobuf.pc
+.deps
+stamp-h1
+
+# in-tree build products
+*.o
+*.lo
+*.la
+src/.libs
+*.so
+
+.dirstamp
+
+any_test.pb.*
+map*unittest.pb.*
+unittest*.pb.*
+cpp_test*.pb.*
+src/google/protobuf/util/**/*.pb.cc
+src/google/protobuf/util/**/*.pb.h
+
+*.pyc
+*.egg-info
+*_pb2.py
+python/*.egg
+python/.eggs/
+python/.tox
+python/build/
+python/google/protobuf/compiler/
+
+src/protoc
+src/unittest_proto_middleman
+
+# Generated test scaffolding
+src/protobuf*-test
+src/test_plugin
+src/testzip.*
+src/zcg*zip
+ar-lib
+
+test-driver
+compile
+
+src/**/*.log
+src/**/*.trs
+
+# JavaBuild output.
+java/target
+javanano/target
+
+# Windows native output.
+cmake/build
+build_msvc
+
+# NuGet packages: we want the repository configuration, but not the
+# packages themselves.
+/csharp/src/packages/*/
+
+# Directories created by opening the Objective C Xcode projects.
+objectivec/ProtocolBuffers_OSX.xcodeproj/project.xcworkspace/xcuserdata/
+objectivec/ProtocolBuffers_OSX.xcodeproj/project.xcworkspace/xcshareddata/ProtocolBuffers_OSX.xccheckout
+objectivec/ProtocolBuffers_OSX.xcodeproj/xcuserdata/
+objectivec/ProtocolBuffers_iOS.xcodeproj/project.xcworkspace/xcuserdata/
+objectivec/ProtocolBuffers_iOS.xcodeproj/project.xcworkspace/xcshareddata/ProtocolBuffers_iOS.xccheckout
+objectivec/ProtocolBuffers_iOS.xcodeproj/xcuserdata/
+# OS X's Finder creates these for state about opened windows/etc.
+**/.DS_Store
+
+# Comformance test output
+conformance/.libs/
+conformance/com/
+conformance/conformance-cpp
+conformance/conformance-csharp
+conformance/conformance-java
+conformance/conformance-objc
+conformance/conformance-test-runner
+conformance/conformance.pb.cc
+conformance/conformance.pb.h
+conformance/Conformance.pbobjc.h
+conformance/Conformance.pbobjc.m
+conformance/conformance.rb
+conformance/javac_middleman
+conformance/protoc_middleman