=all #13783 replace protobuf dependency by embedded version

- created new subproject akka-protobuf (and added COPYING and LICENSE)
- renamed com.google.protobuf -> akka.protobuf everywhere
- also added such renaming step to the results of protoc compilation in
  project/Protobuf.scala
- had to include transcriptions of Netty’s ProtobufEncoder/Decoder to
  make multi-node-testkit compile again

akka-protobuf/src/main/java/akka/protobuf/UninitializedMessageException.java

@@ -0,0 +1,99 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package akka.protobuf;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Thrown when attempting to build a protocol message that is missing required
+ * fields.  This is a {@code RuntimeException} because it normally represents
+ * a programming error:  it happens when some code which constructs a message
+ * fails to set all the fields.  {@code parseFrom()} methods <b>do not</b>
+ * throw this; they throw an {@link InvalidProtocolBufferException} if
+ * required fields are missing, because it is not a programming error to
+ * receive an incomplete message.  In other words,
+ * {@code UninitializedMessageException} should never be thrown by correct
+ * code, but {@code InvalidProtocolBufferException} might be.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public class UninitializedMessageException extends RuntimeException {
+  private static final long serialVersionUID = -7466929953374883507L;
+
+  public UninitializedMessageException(final MessageLite message) {
+    super("Message was missing required fields.  (Lite runtime could not " +
+          "determine which fields were missing).");
+    missingFields = null;
+  }
+
+  public UninitializedMessageException(final List<String> missingFields) {
+    super(buildDescription(missingFields));
+    this.missingFields = missingFields;
+  }
+
+  private final List<String> missingFields;
+
+  /**
+   * Get a list of human-readable names of required fields missing from this
+   * message.  Each name is a full path to a field, e.g. "foo.bar[5].baz".
+   * Returns null if the lite runtime was used, since it lacks the ability to
+   * find missing fields.
+   */
+  public List<String> getMissingFields() {
+    return Collections.unmodifiableList(missingFields);
+  }
+
+  /**
+   * Converts this exception to an {@link InvalidProtocolBufferException}.
+   * When a parsed message is missing required fields, this should be thrown
+   * instead of {@code UninitializedMessageException}.
+   */
+  public InvalidProtocolBufferException asInvalidProtocolBufferException() {
+    return new InvalidProtocolBufferException(getMessage());
+  }
+
+  /** Construct the description string for this exception. */
+  private static String buildDescription(final List<String> missingFields) {
+    final StringBuilder description =
+      new StringBuilder("Message missing required fields: ");
+    boolean first = true;
+    for (final String field : missingFields) {
+      if (first) {
+        first = false;
+      } else {
+        description.append(", ");
+      }
+      description.append(field);
+    }
+    return description.toString();
+  }
+}