Adds support for Notification Delegation

- Adds the TrustedWebActivity service to the Android Manifest.
- Adds a variable to build.gradle to enable / disable the service.

Change-Id: I9822a1488f9aabdc61b751c246bb4cae3874a7f9

app/build.gradle

@@ -22,7 +22,8 @@ def twaManifest = [
     launchUrl: '/', // The start path for the TWA. Must be relative to the domain.
     name: 'SVGOMG TWA', // The name shown on the Android Launcher.
     themeColor: '#303F9F', // The color used for the status bar.
-    backgroundColor: '#bababa' // The color used for the splash screen background.
+    backgroundColor: '#bababa', // The color used for the splash screen background.
+    enableNotifications: false // Set to true to enable notification delegation
 ]
 
 android {
@@ -65,6 +66,11 @@ android {
 
         // Defines a provider authority fot the Splash Screen
         resValue "string", "providerAuthority", twaManifest.applicationId + '.fileprovider'
+
+        // The enableNotification resource is used to enable or disable the
+        // TrustedWebActivityService, by changing the android:enabled and android:exported
+        // attributes
+        resValue "bool", "enableNotification", twaManifest.enableNotifications.toString()
     }
     buildTypes {
         release {

app/src/main/AndroidManifest.xml

@@ -78,5 +78,16 @@
                 android:resource="@xml/filepaths" />
         </provider>
 
+        <service
+             android:name="android.support.customtabs.trusted.TrustedWebActivityService"
+             android:enabled="@bool/enableNotification"
+             android:exported="@bool/enableNotification">
+
+             <intent-filter>
+                 <action android:name="android.support.customtabs.trusted.TRUSTED_WEB_ACTIVITY_SERVICE"/>
+                 <category android:name="android.intent.category.DEFAULT"/>
+             </intent-filter>
+         </service>
+
     </application>
 </manifest>