Add observers for DIP scale change.

content/public/android/java/src/org/chromium/content/common/ContentSwitches.java

 // 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.common;
 
 /**
  * Contains all of the command line switches that are specific to the content/
  * portion of Chromium on Android.
  */
@@ skipping 31 matching lines @@
 
     // Native switch - chrome_switches::kEnableInstantExtendedAPI
     public static final String ENABLE_INSTANT_EXTENDED_API = "enable-instant-extended-api";
 
     // Native switch - shell_switches::kRunLayoutTest
     public static final String RUN_LAYOUT_TEST = "run-layout-test";
 
     // Native switch - chrome_switches::kDisablePopupBlocking
     public static final String DISABLE_POPUP_BLOCKING = "disable-popup-blocking";
 
-    // Native switch - gfx_switches::kForceDeviceScaleFactor
-    public static final String FORCE_DEVICE_SCALE_FACTOR =
-            "force-device-scale-factor";
-
     // Enable mouse hover emulation by holding your finger just over the screen.
     public static final String ENABLE_TOUCH_HOVER = "enable-touch-hover";
 
     // Native switch kEnableCredentialManagerAPI
     public static final String ENABLE_CREDENTIAL_MANAGER_API = "enable-credential-manager-api";
 
     // Native switch kDisableGestureRequirementForMediaPlayback
     public static final String DISABLE_GESTURE_REQUIREMENT_FOR_MEDIA_PLAYBACK =
             "disable-gesture-requirement-for-media-playback";
 
@@ skipping 32 matching lines @@
         // This format should be matched with the one defined in command_line.h.
         final String switchKeyPrefix = "--" + switchKey + "=";
         for (String command : commandLine) {
             if (command != null && command.startsWith(switchKeyPrefix)) {
                 return command.substring(switchKeyPrefix.length());
             }
         }
         return null;
     }
 }