Pass all intent extras needed to render splash screen when launching WebAPK

chrome/android/webapk/shell_apk/BUILD.gn

Index: chrome/android/webapk/shell_apk/BUILD.gn
diff --git a/chrome/android/webapk/shell_apk/BUILD.gn b/chrome/android/webapk/shell_apk/BUILD.gn
index 328b77a3b2ba028e556453484c29a1b730090eac..03c48da7a1f6f7132d1d6ea502508b0098e0b629 100644
--- a/chrome/android/webapk/shell_apk/BUILD.gn
+++ b/chrome/android/webapk/shell_apk/BUILD.gn
@@ -9,16 +9,23 @@ declare_args() {
   # WebAPK. Example: "foo.com"
   webapk_manifest_package_origin = "template"
 
-  # The URL that the WebAPK should navigate to when it is launched.
-  webapk_start_url = "https://www.template.com/home_page"
-
   # The browser that the WebAPK will be bound to.
   webapk_runtime_host = "com.google.android.apps.chrome"
 
-  # The scope of the urls that the WebAPK can navigate to.
+  # 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
+
+  # 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|.
+  # Host part of |webapk_scope_url|.
   webapk_scope_url_host = "www.template.com"
 }
 
@@ -33,9 +40,16 @@ jinja_template("shell_apk_manifest") {
 
   variables = [
     "manifest_package=$shell_apk_manifest_package",
-    "host_url=$webapk_start_url",
     "runtime_host=$webapk_runtime_host",
+    "start_url=$webapk_start_url",
+    "name=$webapk_name",
+    "short_name=$webapk_short_name",
     "scope_url=$webapk_scope_url",
+    "display_mode=$webapk_display_mode",
+    "orientation=$webapk_orientation",
+    "theme_color=$webapk_theme_color",
+    "background_color=$webapk_background_color",
+    "icon_url=$webapk_icon_url",
     "scope_url_host=$webapk_scope_url_host",
   ]
 }