Factor creation of RawInput instances out to RawInputUtil

There are several places where a new RawInput is created. Factor these
out to static methods in a new RawInputUtil class in gerrit-common.

Inspired-by: David Ostrovsky <david@ostrovsky.org>
Change-Id: I10b099e269427b0f887bfb41bbb3f10f46cf2620

gerrit-common/src/main/java/com/google/gerrit/common/RawInputUtil.java

@@ -0,0 +1,76 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.common;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.base.Preconditions;
+import com.google.gerrit.extensions.restapi.RawInput;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.servlet.http.HttpServletRequest;
+
+public class RawInputUtil {
+  public static RawInput create(String content) {
+    return create(content.getBytes(UTF_8));
+  }
+
+  public static RawInput create(final byte[] bytes, final String contentType) {
+    Preconditions.checkNotNull(bytes);
+    Preconditions.checkArgument(bytes.length > 0);
+    return new RawInput() {
+      @Override
+      public InputStream getInputStream() throws IOException {
+        return new ByteArrayInputStream(bytes);
+      }
+
+      @Override
+      public String getContentType() {
+        return contentType;
+      }
+
+      @Override
+      public long getContentLength() {
+        return bytes.length;
+      }
+    };
+  }
+
+  public static RawInput create(final byte[] bytes) {
+    return create (bytes, "application/octet-stream");
+  }
+
+  public static RawInput create(final HttpServletRequest req) {
+    return new RawInput() {
+      @Override
+      public String getContentType() {
+        return req.getContentType();
+      }
+
+      @Override
+      public long getContentLength() {
+        return req.getContentLength();
+      }
+
+      @Override
+      public InputStream getInputStream() throws IOException {
+        return req.getInputStream();
+      }
+    };
+  }
+}