Add observers for DIP scale change.

ui/android/BUILD.gn

Index: ui/android/BUILD.gn
diff --git a/ui/android/BUILD.gn b/ui/android/BUILD.gn
index 96219d786bee9caf035e15fddf7a5e669fed68d0..24d61cf2f307066b258c62061a3a173d19e271df 100644
--- a/ui/android/BUILD.gn
+++ b/ui/android/BUILD.gn
@@ -161,6 +161,7 @@ android_library("ui_java") {
     "java/src/org/chromium/ui/base/AndroidPermissionDelegate.java",
     "java/src/org/chromium/ui/base/Clipboard.java",
     "java/src/org/chromium/ui/base/DeviceFormFactor.java",
+    "java/src/org/chromium/ui/base/DIPScaleListener.java",
     "java/src/org/chromium/ui/base/LocalizationUtils.java",
     "java/src/org/chromium/ui/base/ResourceBundle.java",
     "java/src/org/chromium/ui/base/SelectFileDialog.java",
@@ -169,6 +170,7 @@ android_library("ui_java") {
     "java/src/org/chromium/ui/base/WindowAndroid.java",
     "java/src/org/chromium/ui/gfx/BitmapHelper.java",
     "java/src/org/chromium/ui/gfx/DeviceDisplayInfo.java",
+    "java/src/org/chromium/ui/gfx/DisplaySwitches.java",
     "java/src/org/chromium/ui/gfx/ViewConfigurationHelper.java",
     "java/src/org/chromium/ui/gl/SurfaceTextureListener.java",
     "java/src/org/chromium/ui/gl/SurfaceTexturePlatformWrapper.java",