Add observers for DIP scale change.

components/external_video_surface/BUILD.gn

 # Copyright 2015 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.
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 source_set("external_video_surface") {
   if (is_android) {
@@ skipping 12 matching lines @@
     ]
   }
 }
 
 if (is_android) {
   android_library("java") {
     java_files = [ "android/java/src/org/chromium/components/external_video_surface/ExternalVideoSurfaceContainer.java" ]
     deps = [
       "//base:base_java",
       "//content/public/android:content_java",
+      "//ui/android:ui_java",

[boliu, 2016/09/14 04:35:32]

what does this have to do with this CL?

[Tima Vaisburd, 2016/09/15 00:05:03]

I do not know myself. I have a build problem that this dependency does not
propagate. It cannot see DisplayObserver.

Which makes me think: maybe ContentViewCore should not inherit DisplayObserver,
and instead contain it?

[boliu, 2016/09/15 05:27:41]

That's not ok. Understand the issue, not patch a random fix in that just makes
the problem worse.
Shouldn't matter either way I think

[Tima Vaisburd, 2016/09/16 23:59:25]

Acknowledged.

     ]
   }
   generate_jni("jni_headers") {
     sources = [
       "android/java/src/org/chromium/components/external_video_surface/ExternalVideoSurfaceContainer.java",
     ]
     jni_package = "external_video_surface"
   }
 }