custom-tabs: Add and deliver the start/finish navigation callbacks.

chrome/android/java_staging/src/org/chromium/chrome/browser/customtabs/IBrowserConnectionCallback.aidl

Index: chrome/android/java_staging/src/org/chromium/chrome/browser/customtabs/IBrowserConnectionCallback.aidl
diff --git a/chrome/android/java_staging/src/org/chromium/chrome/browser/customtabs/IBrowserConnectionCallback.aidl b/chrome/android/java_staging/src/org/chromium/chrome/browser/customtabs/IBrowserConnectionCallback.aidl
index aa4b2dcaaeac3cce7122b410eb4ba71dfde463b7..dd52f15b78f75ea10512548ee4f296b219415238 100644
--- a/chrome/android/java_staging/src/org/chromium/chrome/browser/customtabs/IBrowserConnectionCallback.aidl
+++ b/chrome/android/java_staging/src/org/chromium/chrome/browser/customtabs/IBrowserConnectionCallback.aidl
@@ -11,11 +11,20 @@ import android.os.Bundle;
  */
 interface IBrowserConnectionCallback {
     /**
-     * To be called when the user triggers an external navigation.
+     * To be called when a page navigation starts.
      *
      * @param sessionId As returned by {@link IBrowserConnectionService#newSession}.
      * @param url URL the user has navigated to.
      * @param extras Reserved for future use.
      */
-    void onUserNavigation(long sessionId, String url, in Bundle extras);
+    oneway void onUserNavigationStarted(long sessionId, String url, in Bundle extras);
+
+    /**
+     * To be called when a page navigation finishes.
+     *
+     * @param sessionId As returned by {@link IBrowserConnectionService#newSession}.
+     * @param url URL the user has navigated to.
+     * @param extras Reserved for future use.
+     */
+    oneway void onUserNavigationFinished(long sessionId, String url, in Bundle extras);
 }