ash: HiDPI user avatar for SessionController

ui/gfx/image/mojo/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.
+
+import("//mojo/public/tools/bindings/mojom.gni")
+
+mojom("interfaces") {
+  sources = [
+    "image_skia.mojom",

[msw, 2017/03/23 20:47:51]

optional: do you think it'd make sense to name this image.mojom and hope that
we'll get a struct corresponding to gfx::Image here soon?

[xiyuan, 2017/03/24 05:45:19]

Done.

+  ]
+
+  public_deps = [
+    "//skia/public/interfaces",

[msw, 2017/03/23 20:47:51]

I'm not sure this dependency is necessary (not used in mojom)

[xiyuan, 2017/03/24 05:45:19]

Done.

+  ]
+}
+
+source_set("struct_traits") {
+  sources = [
+    "image_skia_struct_traits.cc",
+    "image_skia_struct_traits.h",
+  ]
+
+  public_deps = [
+    ":interfaces_shared_cpp_sources",
+    "//skia/public/interfaces",
+    "//ui/gfx",
+  ]
+}
+
+mojom("test_interfaces") {
+  sources = [
+    "image_traits_test_service.mojom",

[msw, 2017/03/23 20:47:51]

Hopefully we can testing the struct traits without a test service.
See the recent "Testing typemaps" mail:  
https://groups.google.com/a/chromium.org/d/topic/chromium-mojo/_m5qIDZgAf8/di...
I used that guidance to add this test:
https://cs.chromium.org/chromium/src/ash/public/cpp/shelf_struct_traits_unitt...

[xiyuan, 2017/03/24 05:45:19]

Good to know. Ken confirmed that it does not support handles ATM. I will keep
using this test service for all test cases to make it consistent. Add a comment
of why a test service is used.

+  ]
+
+  public_deps = [
+    ":interfaces",
+  ]
+}
+
+source_set("unit_test") {
+  testonly = true
+
+  sources = [
+    "image_traits_unittest.cc",
+  ]
+
+  deps = [
+    ":struct_traits",
+    ":test_interfaces",
+    "//base",
+    "//mojo/public/cpp/bindings",
+    "//testing/gtest",
+  ]
+}