Update //third_party/protobuf to version 3.

third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java

Index: third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java
diff --git a/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java b/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java
new file mode 100644
index 0000000000000000000000000000000000000000..87973d76f07034249d833abbc5e4dfb4236eb238
--- /dev/null
+++ b/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java
@@ -0,0 +1,169 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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 com.google.protobuf.nano;
+
+import java.io.IOException;
+
+/**
+ * Base class of those Protocol Buffer messages that need to store unknown fields,
+ * such as extensions.
+ */
+public abstract class ExtendableMessageNano<M extends ExtendableMessageNano<M>>
+        extends MessageNano {
+    /**
+     * A container for fields unknown to the message, including extensions. Extension fields can
+     * can be accessed through the {@link #getExtension} and {@link #setExtension} methods.
+     */
+    protected FieldArray unknownFieldData;
+
+    @Override
+    protected int computeSerializedSize() {
+        int size = 0;
+        if (unknownFieldData != null) {
+            for (int i = 0; i < unknownFieldData.size(); i++) {
+                FieldData field = unknownFieldData.dataAt(i);
+                size += field.computeSerializedSize();
+            }
+        }
+        return size;
+    }
+
+    @Override
+    public void writeTo(CodedOutputByteBufferNano output) throws IOException {
+        if (unknownFieldData == null) {
+            return;
+        }
+        for (int i = 0; i < unknownFieldData.size(); i++) {
+            FieldData field = unknownFieldData.dataAt(i);
+            field.writeTo(output);
+        }
+    }
+
+    /**
+     * Checks if there is a value stored for the specified extension in this
+     * message.
+     */
+    public final boolean hasExtension(Extension<M, ?> extension) {
+        if (unknownFieldData == null) {
+            return false;
+        }
+        FieldData field = unknownFieldData.get(WireFormatNano.getTagFieldNumber(extension.tag));
+        return field != null;
+    }
+
+    /**
+     * Gets the value stored in the specified extension of this message.
+     */
+    public final <T> T getExtension(Extension<M, T> extension) {
+        if (unknownFieldData == null) {
+            return null;
+        }
+        FieldData field = unknownFieldData.get(WireFormatNano.getTagFieldNumber(extension.tag));
+        return field == null ? null : field.getValue(extension);
+    }
+
+    /**
+     * Sets the value of the specified extension of this message.
+     */
+    public final <T> M setExtension(Extension<M, T> extension, T value) {
+        int fieldNumber = WireFormatNano.getTagFieldNumber(extension.tag);
+        if (value == null) {
+            if (unknownFieldData != null) {
+                unknownFieldData.remove(fieldNumber);
+                if (unknownFieldData.isEmpty()) {
+                    unknownFieldData = null;
+                }
+            }
+        } else {
+            FieldData field = null;
+            if (unknownFieldData == null) {
+                unknownFieldData = new FieldArray();
+            } else {
+                field = unknownFieldData.get(fieldNumber);
+            }
+            if (field == null) {
+                unknownFieldData.put(fieldNumber, new FieldData(extension, value));
+            } else {
+                field.setValue(extension, value);
+            }
+        }
+
+        @SuppressWarnings("unchecked") // Generated code should guarantee type safety
+        M typedThis = (M) this;
+        return typedThis;
+    }
+
+    /**
+     * Stores the binary data of an unknown field.
+     *
+     * <p>Generated messages will call this for unknown fields if the store_unknown_fields
+     * option is on.
+     *
+     * <p>Note that the tag might be a end-group tag (rather than the start of an unknown field) in
+     * which case we do not want to add an unknown field entry.
+     *
+     * @param input the input buffer.
+     * @param tag the tag of the field.
+
+     * @return {@literal true} unless the tag is an end-group tag.
+     */
+    protected final boolean storeUnknownField(CodedInputByteBufferNano input, int tag)
+            throws IOException {
+        int startPos = input.getPosition();
+        if (!input.skipField(tag)) {
+            return false;  // This wasn't an unknown field, it's an end-group tag.
+        }
+        int fieldNumber = WireFormatNano.getTagFieldNumber(tag);
+        int endPos = input.getPosition();
+        byte[] bytes = input.getData(startPos, endPos - startPos);
+        UnknownFieldData unknownField = new UnknownFieldData(tag, bytes);
+
+        FieldData field = null;
+        if (unknownFieldData == null) {
+            unknownFieldData = new FieldArray();
+        } else {
+            field = unknownFieldData.get(fieldNumber);
+        }
+        if (field == null) {
+            field = new FieldData();
+            unknownFieldData.put(fieldNumber, field);
+        }
+        field.addUnknownField(unknownField);
+        return true;
+    }
+
+    @Override
+    public M clone() throws CloneNotSupportedException {
+        M cloned = (M) super.clone();
+        InternalNano.cloneUnknownFieldData(this, cloned);
+        return cloned;
+    }
+}