Android: Don't destroy LayerTreeHost when Surface goes away

ui/android/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.
 
 import("//build/config/android/rules.gni")
 import("//testing/test.gni")
 
 assert(is_android)
 
 component("android") {
   output_name = "ui_android"
   sources = [
     "resources/resource_manager.cc",
     "resources/resource_manager.h",
     "resources/resource_manager_impl.cc",
     "resources/resource_manager_impl.h",
-    "resources/ui_resource_android.cc",
-    "resources/ui_resource_android.h",
-    "resources/ui_resource_client_android.h",
-    "resources/ui_resource_provider.cc",
     "resources/ui_resource_provider.h",
     "ui_android_export.h",
     "ui_android_jni_registrar.cc",
     "ui_android_jni_registrar.h",
     "view_android.cc",
     "view_android.h",
     "window_android.cc",
     "window_android.h",
     "window_android_compositor.h",
     "window_android_observer.h",
   ]
 
   defines = [ "UI_ANDROID_IMPLEMENTATION" ]
 
   deps = [
     "//base",
     "//cc",
     "//skia",
+    "//testing/gmock",
     "//ui/gfx",
     "//ui/gfx/geometry",
     ":ui_android_jni_headers",
   ]
 }
 
 generate_jni("ui_android_jni_headers") {
   sources = [
     "java/src/org/chromium/ui/base/WindowAndroid.java",
     "java/src/org/chromium/ui/resources/ResourceManager.java",
@@ skipping 112 matching lines @@
     "//base/test:test_support",
     "//cc",
     "//skia",
     "//testing/gtest",
     "//ui/base",
     "//ui/gfx",
     "//ui/resources:ui_test_pak",
   ]
   apk_deps = [ ":ui_java" ]
 }