Add postMessage APIs to the support lib

customtabs/src/android/support/customtabs/ICustomTabsCallback.aidl

Index: customtabs/src/android/support/customtabs/ICustomTabsCallback.aidl
diff --git a/customtabs/src/android/support/customtabs/ICustomTabsCallback.aidl b/customtabs/src/android/support/customtabs/ICustomTabsCallback.aidl
index a4678640cf672dca09d672e0dca17b7bb5912be2..c0b8ebe625f72d467e6937c7aef12746a21d5cb3 100644
--- a/customtabs/src/android/support/customtabs/ICustomTabsCallback.aidl
+++ b/customtabs/src/android/support/customtabs/ICustomTabsCallback.aidl
@@ -22,7 +22,9 @@ import android.os.Bundle;
  * Interface to a CustomTabsCallback.
  * @hide
  */
-oneway interface ICustomTabsCallback {
-    void onNavigationEvent(int navigationEvent, in Bundle extras) = 1;
-    void extraCallback(String callbackName, in Bundle args) = 2;
+interface ICustomTabsCallback {
+    oneway void onNavigationEvent(int navigationEvent, in Bundle extras) = 1;
+    oneway void extraCallback(String callbackName, in Bundle args) = 2;
+    oneway void onMessageChannelReady(in Uri origin, in Bundle extras) = 3;

[Benoit L, 2016/11/08 16:27:07]

Sorry, I missed that one in the previous review.

If we want to make sure that the app gets a onMessageChannelReady() before
receiving the first message, do we need to make this call not oneway as well?
(and the method synchronized above)

[Yusuf, 2016/11/08 18:59:10]

Even if we do that, I mean make both syncronized, that won't help with the
ordering between the two methods right? That we basically have to make sure on
the implementation side. I mean we can still fail to make them ordered even with
these two guarantees?

[Yusuf, 2016/11/10 18:48:22]

Done.

+    void onPostMessage(String message, in Bundle extras) = 4;
 }