Remove PopupItemType.template

This Android-specific file isn't used anywhere anymore. Came up while
reviewing Daniel's CL: https://codereview.chromium.org/952443004/

BUG=

Review URL: https://codereview.chromium.org/953543002

Cr-Commit-Position: refs/heads/master@{#317613}

content/public/android/java/src/org/chromium/content/browser/input/PopupItemType.template

-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.content.browser.input;
-
-public class PopupItemType {
-#define DEFINE_POPUP_ITEM_TYPE(name, value) public static final int name = value;
-#include "content/browser/android/popup_item_type_list.h"
-#undef DEFINE_POPUP_ITEM_TYPE
-}