SideBySide2: Display icon during selection to insert comment

Since double click doesn't work on CodeMirror but range selection
does, display a small comment box icon above and to the right of the
end of the selection region.  Clicking this icon will create a new
draft comment on the region.

Change-Id: Id0533b698952d707b720b37fb405e78f1e54e7a8

gerrit-gwtui/src/main/java/net/codemirror/lib/Rect.java

@@ -0,0 +1,28 @@
+// Copyright (C) 2013 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 net.codemirror.lib;
+
+import com.google.gwt.core.client.JavaScriptObject;
+
+/** {left, right, top, bottom} objects used within CodeMirror. */
+public class Rect extends JavaScriptObject {
+  public final native double left() /*-{ return this.left }-*/;
+  public final native double right() /*-{ return this.right }-*/;
+  public final native double top() /*-{ return this.top }-*/;
+  public final native double bottom() /*-{ return this.bottom }-*/;
+
+  protected Rect() {
+  }
+}