fix(android icon): specify color through variable

fix arnesson#53

README.md

@@ -73,6 +73,10 @@ If you want to set a notification icon with another name, pass it through variab
 
 `cordova plugin add cordova-plugin-firebase@0.1.25 --save --variable NOTIFICATION_ICON_NAME=my_beautiful_icon_name`
 
+For the background color of the notification icon, the default is #FF00FFFF. You can modify the color by passing it through variable at plugin installation :
+
+`cordova plugin add cordova-plugin-firebase@0.1.25 --save --variable NOTIFICATION_ICON_NAME=my_beautiful_icon_name NOTIFICATION_ICON_COLOR=#000000`
+
 To set a big icon and small icon for notifications, define them through drawable nodes.  
 Create the required styles.xml files and add the icons to the  
 `<projectroot>/res/native/android/res/<drawable-DPI>` folders.  

plugin.xml

@@ -12,6 +12,7 @@ xmlns:android="http://schemas.android.com/apk/res/android">
 
 	<platform name="android">
 		<preference name="NOTIFICATION_ICON_NAME" default="notification_icon"/>
+		<preference name="NOTIFICATION_ICON_COLOR" default="#FF00FFFF"/>
 		<js-module name="FirebasePlugin" src="www/firebase.js">
 			<clobbers target="FirebasePlugin" />
 		</js-module>
@@ -35,6 +36,7 @@ xmlns:android="http://schemas.android.com/apk/res/android">
 		<config-file target="AndroidManifest.xml" parent="/manifest/application">
 			<service android:enabled="true" android:exported="false" android:name="com.google.android.gms.measurement.AppMeasurementService" />
 			<meta-data android:name="com.google.firebase.messaging.default_notification_icon" android:resource="@drawable/$NOTIFICATION_ICON_NAME" />
+			<meta-data android:name="com.google.firebase.messaging.default_notification_color" android:resource="@color/accent" />
 		</config-file>
 		<config-file target="AndroidManifest.xml" parent="/manifest/application">
 			<service android:name="org.apache.cordova.firebase.FirebasePluginMessagingService">
@@ -55,7 +57,9 @@ xmlns:android="http://schemas.android.com/apk/res/android">
 		<source-file src="src/android/FirebasePluginInstanceIDService.java" target-dir="src/org/apache/cordova/firebase" />
 		<source-file src="src/android/FirebasePluginMessagingService.java" target-dir="src/org/apache/cordova/firebase" />
 		<source-file src="src/android/colors.xml" target-dir="res/values" />
-
+		<config-file target="res/values/colors.xml" parent="/resources">
+			<color name="accent">$NOTIFICATION_ICON_COLOR</color>
+		</config-file>
 		<framework src="src/android/build.gradle" custom="true" type="gradleReference" />
 		<framework src="com.google.gms:google-services:+" />
 		<framework src="com.google.android.gms:play-services-tagmanager:+" />

src/android/colors.xml

@@ -2,5 +2,4 @@
 <resources>
     <color name="primary">#FFFFFF00</color>
     <color name="primary_dark">#FF220022</color>
-    <color name="accent">#FF00FFFF</color>
 </resources>