Add browser tests for AppLaunchHandler.

Add browser tests for AppLaunchHandler to verify the restoration
process.

BUG=1146900

Change-Id: Ibeaf262080a24c680718888ee081cc62c5b21a3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2619245
Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843901}

chrome/test/BUILD.gn

@@ -2505,6 +2505,7 @@ if (!is_android) {
         "../browser/chromeos/file_manager/video_player_browsertest.cc",
         "../browser/chromeos/file_manager/video_player_jstest.cc",
         "../browser/chromeos/first_run/drive_first_run_browsertest.cc",
+        "../browser/chromeos/full_restore/app_launch_handler_browsertest.cc",
         "../browser/chromeos/input_method/input_method_engine_browsertests.cc",
         "../browser/chromeos/input_method/native_input_method_engine_browsertest.cc",
         "../browser/chromeos/input_method/textinput_browsertest.cc",