Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/objectivec/GPBExtensionInternals.m

Index: third_party/protobuf/objectivec/GPBExtensionInternals.m
diff --git a/third_party/protobuf/objectivec/GPBExtensionInternals.m b/third_party/protobuf/objectivec/GPBExtensionInternals.m
index 290c82a1bb8203a3bbe702ad4a3b525c40d967f1..7d0dcb2ee9fb67e8bd52122392ad634f3aeeab01 100644
--- a/third_party/protobuf/objectivec/GPBExtensionInternals.m
+++ b/third_party/protobuf/objectivec/GPBExtensionInternals.m
@@ -45,8 +45,6 @@ static id NewSingleValueFromInputStream(GPBExtensionDescriptor *extension,
     __attribute__((ns_returns_retained));
 
 GPB_INLINE size_t DataTypeSize(GPBDataType dataType) {
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wswitch-enum"
   switch (dataType) {
     case GPBDataTypeBool:
       return 1;
@@ -61,7 +59,6 @@ GPB_INLINE size_t DataTypeSize(GPBDataType dataType) {
     default:
       return 0;
   }
-#pragma clang diagnostic pop
 }
 
 static size_t ComputePBSerializedSizeNoTagOfObject(GPBDataType dataType, id object) {
@@ -264,12 +261,6 @@ static void WriteArrayIncludingTagsToCodedOutputStream(
   }
 }
 
-// Direct access is use for speed, to avoid even internally declaring things
-// read/write, etc. The warning is enabled in the project to ensure code calling
-// protos can turn on -Wdirect-ivar-access without issues.
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wdirect-ivar-access"
-
 void GPBExtensionMergeFromInputStream(GPBExtensionDescriptor *extension,
                                       BOOL isPackedOnStream,
                                       GPBCodedInputStream *input,
@@ -387,5 +378,3 @@ static id NewSingleValueFromInputStream(GPBExtensionDescriptor *extension,
 
   return nil;
 }
-
-#pragma clang diagnostic pop