Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

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")
 
 declare_args() {
   # The origin URL of the WebAPK. Used to generate a unique package name for
   # WebAPK. Example: "foo.com"
   webapk_manifest_package_origin = "template"
 
   # The browser that the WebAPK will be bound to.
   webapk_runtime_host = "com.google.android.apps.chrome"
 
   # The Url of the Web Manifest file.
   webapk_web_manifest_url = "https://www.template.com/manifest.json"
 
   # Attributes from Web Manifest.
   webapk_start_url = "https://www.template.com/home_page"
   webapk_name = "Longer Sample WebAPK Name"
   webapk_short_name = "Sample WebAPK"
   webapk_scope_url = "https://www.template.com"
   webapk_display_mode = "standalone"
   webapk_orientation = "portrait"
-  webapk_theme_color = "4288230399L"  #0xFF9933FF
-  webapk_background_color = "4291624959L"  #0xFFCCFFFF
+  webapk_theme_color = "2147483648L"

[pkotwicz, 2016/07/19 18:02:37]

Can you add a comment as to what this number represents?
Perhaps:
webapk_theme_color = "2147483648L"  #
HostBrowserLauncher#MANIFEST_COLOR_INVALID_OR_MISSING

[Xi Han, 2016/07/20 18:54:59]

Done.

+  webapk_background_color = "2147483648L"
 
   # The URL of the app icon. Empty if the app icon is generated.
   webapk_icon_url = "http://www.template.com/icon.png"
 
   # Host part of |webapk_scope_url|.
   webapk_scope_url_host = "www.template.com"
 }
 
 shell_apk_manifest_package =
     "org.chromium.webapk.$webapk_manifest_package_origin"
@@ skipping 63 matching lines @@
       [ "javatests/src/org/chromium/webapk/shell_apk/DexLoaderTest.java" ]
   deps = [
     ":dex_loader_java",
     "//base:base_java",
     "//base:base_java_test_support",
     "//chrome/android/webapk/libs/common:common_java",
     "//content/public/test/android:content_java_test_support",
   ]
   srcjar_deps = [ "javatests/dex_optimizer:dex_optimizer_service_aidl" ]
 }