[CRD iOS] Move UI stuff into a subdirectory

remoting/client/ui/BUILD.gn

+# Copyright 2017 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.
+
+source_set("ui") {
+  sources = [
+    "desktop_viewport.cc",
+    "desktop_viewport.h",
+    "direct_input_strategy.cc",
+    "direct_input_strategy.h",
+    "fling_animation.cc",
+    "fling_animation.h",
+    "fling_tracker.cc",
+    "fling_tracker.h",
+    "gesture_interpreter.cc",
+    "gesture_interpreter.h",
+    "input_strategy.h",
+    "view_matrix.cc",
+    "view_matrix.h",
+  ]
+
+  public_deps = [
+    "//remoting/proto",
+    "//third_party/webrtc/base:rtc_base_approved",
+  ]
+}
+
+source_set("unit_tests") {
+  testonly = true
+
+  sources = [
+    "desktop_viewport_unittest.cc",
+    "fling_animation_unittest.cc",
+  ]
+
+  configs += [ "//remoting/build/config:version" ]
+
+  deps = [
+    ":ui",
+    "//testing/gmock",
+    "//testing/gtest",
+  ]
+}