Add observers for DIP scale change.

ui/android/java/src/org/chromium/ui/gfx/DisplaySwitches.java

Index: ui/android/java/src/org/chromium/ui/gfx/DisplaySwitches.java
diff --git a/ui/android/java/src/org/chromium/ui/gfx/DisplaySwitches.java b/ui/android/java/src/org/chromium/ui/gfx/DisplaySwitches.java
new file mode 100644
index 0000000000000000000000000000000000000000..c90884102867c6cb9b9c936fa32f22b642498163
--- /dev/null
+++ b/ui/android/java/src/org/chromium/ui/gfx/DisplaySwitches.java
@@ -0,0 +1,17 @@
+// Copyright 2016 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.ui.gfx;
+
+/**
+ * Contains all of the command line switches that are specific to the ui/gfx
+ * portion of Chromium on Android.
+ */
+public abstract class DisplaySwitches {
+    // Native switch - display_switches::kForceDeviceScaleFactor
+    public static final String FORCE_DEVICE_SCALE_FACTOR = "force-device-scale-factor";
+
+    // Prevent instantiation.
+    private DisplaySwitches() {}
+}