Handle app custom icon via aura::Window property.

chrome/browser/ui/test/test_app_window_icon_observer.cc

+// 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.
+
+#include "chrome/browser/ui/test/test_app_window_icon_observer.h"
+
+#include "base/run_loop.h"
+#include "extensions/browser/app_window/app_window.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/window.h"
+
+TestAppWindowIconObserver::TestAppWindowIconObserver(
+    content::BrowserContext* context)
+    : context_(context) {
+  extensions::AppWindowRegistry::Get(context_)->AddObserver(this);
+}
+
+TestAppWindowIconObserver::~TestAppWindowIconObserver() {
+  extensions::AppWindowRegistry::Get(context_)->RemoveObserver(this);
+  for (aura::Window* window : windows_)
+    window->RemoveObserver(this);
+}
+
+void TestAppWindowIconObserver::WaitForIconUpdate() {
+  WaitForIconUpdates(1);
+}
+
+void TestAppWindowIconObserver::WaitForIconUpdates(int updates) {
+  base::RunLoop run_loop;
+  expected_icon_updates_ = updates + icon_updates_;
+  icon_updated_callback_ = run_loop.QuitClosure();
+  run_loop.Run();
+}
+
+void TestAppWindowIconObserver::OnAppWindowAdded(
+    extensions::AppWindow* app_window) {
+  aura::Window* window = app_window->GetNativeWindow();
+  window->AddObserver(this);
+  windows_.push_back(window);
+}
+
+void TestAppWindowIconObserver::OnAppWindowRemoved(
+    extensions::AppWindow* app_window) {
+  aura::Window* window = app_window->GetNativeWindow();
+  if (window) {
+    windows_.erase(std::find(windows_.begin(), windows_.end(), window));
+    window->RemoveObserver(this);
+  }
+}
+
+void TestAppWindowIconObserver::OnWindowPropertyChanged(aura::Window* window,
+                                                        const void* key,
+                                                        intptr_t old) {
+  if (key == aura::client::kAppIconKey) {
+    ++icon_updates_;
+    if (icon_updates_ == expected_icon_updates_ &&
+        !icon_updated_callback_.is_null()) {
+      base::ResetAndReturn(&icon_updated_callback_).Run();
+    }
+  }
+}