third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/patches/0009-uninline-arenastring.patch

Index: third_party/protobuf/patches/0009-uninline-arenastring.patch
diff --git a/third_party/protobuf/patches/0009-uninline-arenastring.patch b/third_party/protobuf/patches/0009-uninline-arenastring.patch
index 6ba6360b35c034df083b2a561b8d19eab61798e4..04fc0322c1b5733c5080dc9dad668de5d5b4ddf6 100644
--- a/third_party/protobuf/patches/0009-uninline-arenastring.patch
+++ b/third_party/protobuf/patches/0009-uninline-arenastring.patch
@@ -29,9 +29,9 @@ only in patch2:
 unchanged:
 --- protobuf-cleaned/src/google/protobuf/arenastring.h	2015-12-30 13:21:46.000000000 -0800
 +++ protobuf-patched/src/google/protobuf/arenastring.h	2016-03-31 13:25:40.888006485 -0700
-@@ -219,12 +219,7 @@
-     return *ptr_;
-   }
+@@ -214,12 +214,7 @@ struct LIBPROTOBUF_EXPORT ArenaStringPtr {
+ 
+   inline const ::std::string& GetNoArena() const { return *ptr_; }
  
 -  inline ::std::string* MutableNoArena(const ::std::string* default_value) {
 -    if (ptr_ == default_value) {
@@ -43,7 +43,7 @@ unchanged:
  
    inline ::std::string* ReleaseNoArena(const ::std::string* default_value) {
      if (ptr_ == default_value) {
-@@ -248,12 +243,7 @@
+@@ -243,11 +238,7 @@ struct LIBPROTOBUF_EXPORT ArenaStringPtr {
      }
    }
  
@@ -51,7 +51,6 @@ unchanged:
 -    if (ptr_ != default_value) {
 -      delete ptr_;
 -    }
--    ptr_ = NULL;
 -  }
 +  void DestroyNoArena(const ::std::string* default_value);