Update //third_party/protobuf to version 3.

third_party/protobuf/protobuf_lite.gypi

Index: third_party/protobuf/protobuf_lite.gypi
diff --git a/third_party/protobuf/protobuf_lite.gypi b/third_party/protobuf/protobuf_lite.gypi
index bbdc072715d40317accb90381f75ece670b2f742..28d8878eacfa52ca2942a5fba61204945f3c9748 100644
--- a/third_party/protobuf/protobuf_lite.gypi
+++ b/third_party/protobuf/protobuf_lite.gypi
@@ -4,47 +4,53 @@
 
 {
   'sources': [
-    'src/google/protobuf/stubs/atomicops.h',
-    'src/google/protobuf/stubs/atomicops_internals_arm_gcc.h',
-    'src/google/protobuf/stubs/atomicops_internals_atomicword_compat.h',
-    'src/google/protobuf/stubs/atomicops_internals_macosx.h',
-    'src/google/protobuf/stubs/atomicops_internals_mips_gcc.h',
-    'src/google/protobuf/stubs/atomicops_internals_x86_gcc.cc',
-    'src/google/protobuf/stubs/atomicops_internals_x86_gcc.h',
-    'src/google/protobuf/stubs/atomicops_internals_x86_msvc.cc',
-    'src/google/protobuf/stubs/atomicops_internals_x86_msvc.h',
-    'src/google/protobuf/stubs/common.h',
-    'src/google/protobuf/stubs/once.h',
-    'src/google/protobuf/stubs/platform_macros.h',
+    'src/google/protobuf/arena.cc',
+    'src/google/protobuf/arena.h',
+    'src/google/protobuf/arenastring.cc',
+    'src/google/protobuf/arenastring.h',
+    'src/google/protobuf/extension_set.cc',

[Peter Kasting, 2016/04/06 22:35:39]

This file seems to be missing a lot of the files I had added in
https://codereview.chromium.org/1291903002/diff/110001/third_party/protobuf/p...
, primarily headers (e.g. here it's missing descriptor.h and descriptor_pb.h). 
Did you determine these weren't needed?  (I had constructed my list from the
transitive #includes of all the source files needed, but another way to check
this would be to delete all those headers out of your local source tree
completely and see if the compile still works).

[xyzzyz, 2016/04/07 18:55:02]

This list was prepared by copying the list from the upstream Bazel BUILD file,
and adding .h for every .cc file.

https://github.com/google/protobuf/blob/master/BUILD

[Peter Kasting, 2016/04/07 23:25:38]

We need to list all transitively-included headers, or when someone touches one
of those headers the project may not be rebuilt correctly.

If you have a tool that can do this, awesome, but I did it by literally looking
at all the #includes of every file manually.  It went surprisingly quickly.

When you come up with a list, compare it with the list in my previous update
attempt and ensure any differences are actually correct.

[xyzzyz, 2016/04/11 19:34:40]

I think I got them all this time.

     'src/google/protobuf/extension_set.h',
+    'src/google/protobuf/generated_message_util.cc',
     'src/google/protobuf/generated_message_util.h',
-    'src/google/protobuf/message_lite.h',
-    'src/google/protobuf/repeated_field.h',
-    'src/google/protobuf/unknown_field_set.cc',
-    'src/google/protobuf/unknown_field_set.h',
-    'src/google/protobuf/wire_format_lite.h',
-    'src/google/protobuf/wire_format_lite_inl.h',
+    'src/google/protobuf/io/coded_stream.cc',
     'src/google/protobuf/io/coded_stream.h',
+    'src/google/protobuf/io/zero_copy_stream.cc',
     'src/google/protobuf/io/zero_copy_stream.h',
+    'src/google/protobuf/io/zero_copy_stream_impl_lite.cc',
     'src/google/protobuf/io/zero_copy_stream_impl_lite.h',
-
-    'src/google/protobuf/stubs/common.cc',
-    'src/google/protobuf/stubs/once.cc',
-    'src/google/protobuf/stubs/hash.h',
-    'src/google/protobuf/stubs/map-util.h',
-    'src/google/protobuf/extension_set.cc',
-    'src/google/protobuf/generated_message_util.cc',
     'src/google/protobuf/message_lite.cc',
+    'src/google/protobuf/message_lite.h',
     'src/google/protobuf/repeated_field.cc',
+    'src/google/protobuf/repeated_field.h',
+    'src/google/protobuf/stubs/atomicops_internals_x86_gcc.cc',
+    'src/google/protobuf/stubs/atomicops_internals_x86_gcc.h',
+    'src/google/protobuf/stubs/atomicops_internals_x86_msvc.cc',
+    'src/google/protobuf/stubs/atomicops_internals_x86_msvc.h',
+    'src/google/protobuf/stubs/bytestream.cc',
+    'src/google/protobuf/stubs/bytestream.h',
+    'src/google/protobuf/stubs/common.cc',
+    'src/google/protobuf/stubs/common.h',
+    'src/google/protobuf/stubs/int128.cc',
+    'src/google/protobuf/stubs/int128.h',
+    'src/google/protobuf/stubs/once.cc',
+    'src/google/protobuf/stubs/once.h',
+    'src/google/protobuf/stubs/status.cc',
+    'src/google/protobuf/stubs/status.h',
+    'src/google/protobuf/stubs/statusor.cc',
+    'src/google/protobuf/stubs/statusor.h',
+    'src/google/protobuf/stubs/stringpiece.cc',
+    'src/google/protobuf/stubs/stringpiece.h',
+    'src/google/protobuf/stubs/stringprintf.cc',
+    'src/google/protobuf/stubs/stringprintf.h',
+    'src/google/protobuf/stubs/structurally_valid.cc',
+    'src/google/protobuf/stubs/strutil.cc',
+    'src/google/protobuf/stubs/strutil.h',
+    'src/google/protobuf/stubs/time.cc',
+    'src/google/protobuf/stubs/time.h',
     'src/google/protobuf/wire_format_lite.cc',
-    'src/google/protobuf/io/coded_stream.cc',
-    'src/google/protobuf/io/coded_stream_inl.h',
-    'src/google/protobuf/io/zero_copy_stream.cc',
-    'src/google/protobuf/io/zero_copy_stream_impl_lite.cc',
-    '<(config_h_dir)/config.h',
+    'src/google/protobuf/wire_format_lite.h',
   ],
   'include_dirs': [
-    '<(config_h_dir)',
     'src',
   ],
   # This macro must be defined to suppress the use of dynamic_cast<>,
@@ -55,7 +61,6 @@
   ],
   'direct_dependent_settings': {
     'include_dirs': [
-      '<(config_h_dir)',
       'src',
     ],
     'defines': [