Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

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

Index: third_party/protobuf/java/core/src/main/java/com/google/protobuf/FieldSet.java
diff --git a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/FieldSet.java b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/FieldSet.java
index 5b251743be508ed1555e79a9505976f5c7497a83..4e89709f32cf67837c150fc43654877b995e57d7 100644
--- a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/FieldSet.java
+++ b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/FieldSet.java
@@ -120,21 +120,21 @@ final class FieldSet<FieldDescriptorType extends
   public boolean isImmutable() {
     return isImmutable;
   }
-
+  
   @Override
   public boolean equals(Object o) {
     if (this == o) {
       return true;
     }
-
+    
     if (!(o instanceof FieldSet)) {
       return false;
     }
-
+    
     FieldSet<?> other = (FieldSet<?>) o;
-    return fields.equals(other.fields);
+    return other.fields.equals(other.fields);
   }
-
+  
   @Override
   public int hashCode() {
     return fields.hashCode();
@@ -493,7 +493,7 @@ final class FieldSet<FieldDescriptorType extends
   }
 
   /**
-   * Like {@link Message.Builder#mergeFrom(Message)}, but merges from another
+   * Like {@link Message.Builder#mergeFrom(Message)}, but merges from another 
    * {@link FieldSet}.
    */
   public void mergeFrom(final FieldSet<FieldDescriptorType> other) {
@@ -638,11 +638,10 @@ final class FieldSet<FieldDescriptorType extends
    *               {@link Message#getField(Descriptors.FieldDescriptor)} for
    *               this field.
    */
-  static void writeElement(
-      final CodedOutputStream output,
-      final WireFormat.FieldType type,
-      final int number,
-      final Object value) throws IOException {
+  private static void writeElement(final CodedOutputStream output,
+                                   final WireFormat.FieldType type,
+                                   final int number,
+                                   final Object value) throws IOException {
     // Special case for groups, which need a start and end tag; other fields
     // can just use writeTag() and writeFieldNoTag().
     if (type == WireFormat.FieldType.GROUP) {
@@ -805,8 +804,9 @@ final class FieldSet<FieldDescriptorType extends
    *               {@link Message#getField(Descriptors.FieldDescriptor)} for
    *               this field.
    */
-  static int computeElementSize(
-      final WireFormat.FieldType type, final int number, final Object value) {
+  private static int computeElementSize(
+      final WireFormat.FieldType type,
+      final int number, final Object value) {
     int tagSize = CodedOutputStream.computeTagSize(number);
     if (type == WireFormat.FieldType.GROUP) {
       // Only count the end group tag for proto2 messages as for proto1 the end