Update protobuf to r428, part 1.

third_party/protobuf/java/src/main/java/com/google/protobuf/AbstractMessageLite.java

Index: third_party/protobuf/java/src/main/java/com/google/protobuf/AbstractMessageLite.java
===================================================================
--- third_party/protobuf/java/src/main/java/com/google/protobuf/AbstractMessageLite.java	(revision 216642)
+++ third_party/protobuf/java/src/main/java/com/google/protobuf/AbstractMessageLite.java	(working copy)
@@ -92,6 +92,14 @@
   }
 
   /**
+   * Package private helper method for AbstractParser to create
+   * UninitializedMessageException.
+   */
+  UninitializedMessageException newUninitializedMessageException() {
+    return new UninitializedMessageException(this);
+  }
+
+  /**
    * A partial implementation of the {@link Message.Builder} interface which
    * implements as many methods of that interface as possible in terms of
    * other methods.
@@ -307,10 +315,12 @@
      */
     protected static <T> void addAll(final Iterable<T> values,
                                      final Collection<? super T> list) {
-      for (final T value : values) {
-        if (value == null) {
-          throw new NullPointerException();
-        }
+      if (values instanceof LazyStringList) {
+        // For StringOrByteStringLists, check the underlying elements to avoid
+        // forcing conversions of ByteStrings to Strings.
+        checkForNullValues(((LazyStringList) values).getUnderlyingElements());
+      } else {
+        checkForNullValues(values);
       }
       if (values instanceof Collection) {
         final Collection<T> collection = (Collection<T>) values;
@@ -321,5 +331,13 @@
         }
       }
     }
+
+    private static void checkForNullValues(final Iterable<?> values) {
+      for (final Object value : values) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+      }
+    }
   }
 }