Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/compiler/code_generator.h

Index: third_party/protobuf/src/google/protobuf/compiler/code_generator.h
diff --git a/third_party/protobuf/src/google/protobuf/compiler/code_generator.h b/third_party/protobuf/src/google/protobuf/compiler/code_generator.h
index 252f68d1dc269898a64118fc8dd6015176b98cb0..b989f151328fc7c8e08c5c3fbe2225fd11fb3f7d 100644
--- a/third_party/protobuf/src/google/protobuf/compiler/code_generator.h
+++ b/third_party/protobuf/src/google/protobuf/compiler/code_generator.h
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -79,6 +79,37 @@ class LIBPROTOC_EXPORT CodeGenerator {
                         GeneratorContext* generator_context,
                         string* error) const = 0;
 
+  // Generates code for all given proto files, generating one or more files in
+  // the given output directory.
+  //
+  // This method should be called instead of |Generate()| when
+  // |HasGenerateAll()| returns |true|. It is used to emulate legacy semantics
+  // when more than one `.proto` file is specified on one compiler invocation.
+  //
+  // WARNING: Please do not use unless legacy semantics force the code generator
+  // to produce a single output file for all input files, or otherwise require
+  // an examination of all input files first. The canonical code generator
+  // design produces one output file per input .proto file, and we do not wish
+  // to encourage alternate designs.
+  //
+  // A parameter is given as passed on the command line, as in |Generate()|
+  // above.
+  //
+  // Returns true if successful.  Otherwise, sets *error to a description of
+  // the problem (e.g. "invalid parameter") and returns false.
+  virtual bool GenerateAll(const vector<const FileDescriptor*>& files,
+                           const string& parameter,
+                           GeneratorContext* generator_context,
+                           string* error) const {
+    *error = "Unimplemented GenerateAll() method.";
+    return false;
+  }
+
+  // Returns true if the code generator expects to receive all FileDescriptors
+  // at once (via |GenerateAll()|), rather than one at a time (via
+  // |Generate()|). This is required to implement legacy semantics.
+  virtual bool HasGenerateAll() const { return false; }
+
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CodeGenerator);
 };
@@ -104,6 +135,9 @@ class LIBPROTOC_EXPORT GeneratorContext {
   // contain "." or ".." components.
   virtual io::ZeroCopyOutputStream* Open(const string& filename) = 0;
 
+  // Similar to Open() but the output will be appended to the file if exists
+  virtual io::ZeroCopyOutputStream* OpenForAppend(const string& filename);
+
   // Creates a ZeroCopyOutputStream which will insert code into the given file
   // at the given insertion point.  See plugin.proto (plugin.pb.h) for more
   // information on insertion points.  The default implementation