Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/java/core/src/main/java/com/google/protobuf/NioByteString.java

Index: third_party/protobuf/java/core/src/main/java/com/google/protobuf/NioByteString.java
diff --git a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/NioByteString.java b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/NioByteString.java
index 76594809e8d65de45225c8ecf9ccef32c2c9a94b..6163c7b1a81c3d0c4d35306b399322a179b948a3 100644
--- a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/NioByteString.java
+++ b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/NioByteString.java
@@ -30,8 +30,6 @@
 
 package com.google.protobuf;
 
-import static com.google.protobuf.Internal.checkNotNull;
-
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InvalidObjectException;
@@ -51,9 +49,10 @@ final class NioByteString extends ByteString.LeafByteString {
   private final ByteBuffer buffer;
 
   NioByteString(ByteBuffer buffer) {
-    checkNotNull(buffer, "buffer");
+    if (buffer == null) {
+      throw new NullPointerException("buffer");
+    }
 
-    // Use native byte order for fast fixed32/64 operations.
     this.buffer = buffer.slice().order(ByteOrder.nativeOrder());
   }
 
@@ -267,7 +266,7 @@ final class NioByteString extends ByteString.LeafByteString {
 
   @Override
   public CodedInputStream newCodedInput() {
-    return CodedInputStream.newInstance(buffer, true);
+    return CodedInputStream.newInstance(buffer);
   }
 
   /**