Fix: long-tapping a WebAPK in recents shows Chrome.

chrome/android/webapk/shell_apk/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("shell_apk_version.gni")
 
 declare_args() {
   # The browser that the WebAPK will be bound to.
   webapk_runtime_host = "com.google.android.apps.chrome"
@@ skipping 93 matching lines @@
 android_resources("shell_apk_resources") {
   resource_dirs = [ "res" ]
   custom_package = "org.chromium.webapk.shell_apk"
 }
 
 android_library("webapk_java") {
   java_files = [
     "src/org/chromium/webapk/shell_apk/DexLoader.java",
     "src/org/chromium/webapk/shell_apk/HostBrowserClassLoader.java",
     "src/org/chromium/webapk/shell_apk/MainActivity.java",
+    "src/org/chromium/webapk/shell_apk/LaunchWebApkHelper.java",
     "src/org/chromium/webapk/shell_apk/NotificationSettingsLauncherActivity.java",
+    "src/org/chromium/webapk/shell_apk/RecentsPlaceholderActivity.java",
     "src/org/chromium/webapk/shell_apk/WebApkSandboxedProcessService.java",
     "src/org/chromium/webapk/shell_apk/WebApkSandboxedProcessService0.java",
     "src/org/chromium/webapk/shell_apk/WebApkSandboxedProcessService1.java",
     "src/org/chromium/webapk/shell_apk/WebApkSandboxedProcessService2.java",
     "src/org/chromium/webapk/shell_apk/WebApkServiceFactory.java",
     "src/org/chromium/webapk/shell_apk/WebApkUtils.java",
   ]
   deps = [
     ":shell_apk_resources",
     "//chrome/android/webapk/libs/common:common_java",
@@ skipping 54 matching lines @@
     "//chrome/android/webapk/libs/common:common_java",
     "//content/public/test/android:content_java_test_support",
     "//third_party/android_support_test_runner:runner_java",
   ]
   srcjar_deps = [ "javatests/dex_optimizer:dex_optimizer_service_aidl" ]
 }
 
 junit_binary("webapk_shell_apk_junit_tests") {
   java_files = [
     "junit/src/org/chromium/webapk/shell_apk/HostBrowserClassLoaderTest.java",
-    "junit/src/org/chromium/webapk/shell_apk/MainActivityTest.java",
+    "junit/src/org/chromium/webapk/shell_apk/RecentsPlaceholderActivityTest.java",
   ]
   deps = [
     ":webapk_java",
     "//chrome/android/webapk/libs/common:common_java",
     "//chrome/android/webapk/test:junit_test_support",
   ]
 }