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-acceptance-framework/src/test/java/com/google/gerrit/acceptance/RestSession.java

@@ -28,9 +28,7 @@ import org.apache.http.entity.InputStreamEntity;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.message.BasicHeader;
 
-import java.io.ByteArrayInputStream;
 import java.io.IOException;
-import java.io.InputStream;
 
 public class RestSession extends HttpSession {
 
@@ -113,30 +111,4 @@ public class RestSession extends HttpSession {
   public RestResponse delete(String endPoint) throws IOException {
     return execute(Request.Delete(url + "/a" + endPoint));
   }
-
-
-  public static RawInput newRawInput(String content) {
-    return newRawInput(content.getBytes(UTF_8));
-  }
-
-  public static RawInput newRawInput(final byte[] bytes) {
-    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 "application/octet-stream";
-      }
-
-      @Override
-      public long getContentLength() {
-        return bytes.length;
-      }
-    };
-  }
 }