[System PWAs] Add manifest for Discover App.

This CL adds a manifest for the Discover App so that it installs as a
System PWA with the correct icon, name, and theme color.

Bug: 836128
Change-Id: Idd2d86671caa50a02474a1785972aa7f1d7b1fe7
Reviewed-on: https://chromium-review.googlesource.com/c/1290051
Commit-Queue: calamity <calamity@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603434}

chrome/browser/browser_resources.grd

@@ -40,6 +40,7 @@
         <structure name="IDR_KEYBOARD_UTILS_JS" file="resources\chromeos\keyboard\keyboard_utils.js" flattenhtml="true" type="chrome_html" />
         <structure name="IDR_CHROMEOS_DISCOVER_APP_HTML" file="resources\chromeos\login\discover\discover_app.html" flattenhtml="true" type="chrome_html"/>
         <structure name="IDR_CHROMEOS_DISCOVER_APP_JS" file="resources\chromeos\login\discover\discover_app.js" flattenhtml="true" type="chrome_html"/>
+        <structure name="IDR_CHROMEOS_DISCOVER_MANIFEST" file="resources\chromeos\login\discover\manifest.json" flattenhtml="true" type="chrome_html"/>
         <structure name="IDR_CUSTOM_ELEMENTS_OOBE_HTML" file="resources\chromeos\login\custom_elements_oobe.html" flattenhtml="true" type="chrome_html" />
         <structure name="IDR_CUSTOM_ELEMENTS_OOBE_JS" file="resources\chromeos\login\custom_elements_oobe.js" flattenhtml="true" type="chrome_html" />
         <structure name="IDR_CUSTOM_ELEMENTS_LOCK_HTML" file="resources\chromeos\login\custom_elements_lock.html" flattenhtml="true" type="chrome_html" />

chrome/browser/resources/chromeos/login/discover/discover_app.html

@@ -8,6 +8,7 @@
     <meta name="google" value="notranslate">
     <title i18n-content="title"></title>
     <link rel="stylesheet" href="discover_app.css">
+    <link rel="manifest" href="chrome://oobe/manifest.json">
     <link rel="import" href="chrome://resources/html/polymer.html">
     <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout-classes.html">
     <link rel="import" href="chrome://resources/html/i18n_behavior.html">

chrome/browser/resources/chromeos/login/discover/manifest.json

+{
+  "short_name": "Discover",
+  "display": "standalone",
+  "icons": [
+    {
+      "src": "chrome://oobe/logo.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    }
+  ],
+  "start_url": "/discover",
+  "theme_color": "#FFFFFF"
+}

chrome/browser/ui/webui/chromeos/login/oobe_ui.cc

@@ -10,6 +10,7 @@
 
 #include "ash/public/cpp/ash_features.h"
 #include "ash/public/cpp/ash_switches.h"
+#include "ash/public/cpp/resources/grit/ash_public_unscaled_resources.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
@@ -224,6 +225,8 @@ void AddLockDisplayTypeDefaultResources(content::WebUIDataSource* source) {
 void AddDiscoverDisplayTypeDefaultResources(content::WebUIDataSource* source) {
   source->SetDefaultResource(IDR_CHROMEOS_DISCOVER_APP_HTML);
   source->AddResourcePath(kDiscoverJSPath, IDR_CHROMEOS_DISCOVER_APP_JS);
+  source->AddResourcePath("manifest.json", IDR_CHROMEOS_DISCOVER_MANIFEST);
+  source->AddResourcePath("logo.png", IDR_DISCOVER_APP_192);
 }
 
 // Default and non-shared resource definition for kLoginDisplay display type.