Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.h

Index: third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.h
diff --git a/third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.h b/third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.h
index 5b1d01ea8782b5093719d002be26a6fefffc625d..fe21c575742d7d4883ab7f4d42d41fd74ead2fe7 100644
--- a/third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.h
+++ b/third_party/protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.h
@@ -46,8 +46,7 @@ namespace cpp {
 
 class EnumFieldGenerator : public FieldGenerator {
  public:
-  explicit EnumFieldGenerator(const FieldDescriptor* descriptor,
-                              const Options& options);
+  EnumFieldGenerator(const FieldDescriptor* descriptor, const Options& options);
   ~EnumFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -74,8 +73,8 @@ class EnumFieldGenerator : public FieldGenerator {
 
 class EnumOneofFieldGenerator : public EnumFieldGenerator {
  public:
-  explicit EnumOneofFieldGenerator(const FieldDescriptor* descriptor,
-                                   const Options& options);
+  EnumOneofFieldGenerator(const FieldDescriptor* descriptor,
+                          const Options& options);
   ~EnumOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -91,8 +90,8 @@ class EnumOneofFieldGenerator : public EnumFieldGenerator {
 
 class RepeatedEnumFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
-                                      const Options& options);
+  RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
+                             const Options& options);
   ~RepeatedEnumFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------