Add postMessage APIs to the support lib

customtabs/src/android/support/customtabs/CustomTabsSessionToken.java

Index: customtabs/src/android/support/customtabs/CustomTabsSessionToken.java
diff --git a/customtabs/src/android/support/customtabs/CustomTabsSessionToken.java b/customtabs/src/android/support/customtabs/CustomTabsSessionToken.java
index 9113eb036a61650d255739016419298deecb9315..d20921737b7877613ea3327decd6ef2a63890749 100644
--- a/customtabs/src/android/support/customtabs/CustomTabsSessionToken.java
+++ b/customtabs/src/android/support/customtabs/CustomTabsSessionToken.java
@@ -17,6 +17,7 @@
 package android.support.customtabs;
 
 import android.content.Intent;
+import android.net.Uri;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.os.RemoteException;
@@ -37,6 +38,12 @@ public class CustomTabsSessionToken {
         public void onNavigationEvent(int navigationEvent, Bundle extras) {}
 
         @Override
+        public void onMessageChannelReady(Uri origin, Bundle extras) {}
+
+        @Override
+        public void onPostMessage(String message, Bundle extras) {}
+
+        @Override
         public void extraCallback(String callbackName, Bundle args) {}
 
         @Override
@@ -84,6 +91,24 @@ public class CustomTabsSessionToken {
             }
 
             @Override
+            public synchronized void onMessageChannelReady(Uri origin, Bundle extras) {
+                try {
+                    mCallbackBinder.onMessageChannelReady(origin, extras);
+                } catch (RemoteException e) {
+                    Log.e(TAG, "RemoteException during ICustomTabsCallback transaction");
+                }
+            }
+
+            @Override
+            public synchronized void onPostMessage(String message, Bundle extras) {
+                try {
+                    mCallbackBinder.onPostMessage(message, extras);
+                } catch (RemoteException e) {
+                    Log.e(TAG, "RemoteException during ICustomTabsCallback transaction");
+                }
+            }
+
+            @Override
             public void extraCallback(String callbackName, Bundle args) {
                 try {
                     mCallbackBinder.extraCallback(callbackName, args);