New method to re-authorize based on an existing auth token

so we don't have to send our users through the subpar already-authorized
login experience.  Store the token and expiration in window.localstorage
and try to reauthorize before you authorize normally.

Android/Facebook/src/com/hipsnip/plugins/facebook/FacebookAuth.java

@@ -54,6 +54,8 @@ public PluginResult execute(String action, JSONArray args, String callbackId) {
 
 		if (action.equals("authorize")) {
 			this.authorize(first); // first arg is APP_ID
+		} else if (action.equals("reauthorize")) {
+			this.reauthorize(first, args); // first arg is APP_ID
 		} else if (action.equals("request")){
 			this.getResponse(first); // first arg is path
 		} else if (action.equals("getAccess")){
@@ -150,13 +152,41 @@ public void authorize(final String appid) {
 		final FacebookAuth fba = this;
 		Runnable runnable = new Runnable() {
 			public void run() {
-				fba.mFb = new Facebook(appid);
-				fba.mFb.setPlugin(fba);
+				if (fba.mFb == null) {
+					fba.mFb = new Facebook(appid);
+					fba.mFb.setPlugin(fba);
+				}
 				fba.mFb.authorize((Activity) fba.ctx, fba.permissions, new AuthorizeListener(fba));
 			};
 		};
 		this.ctx.runOnUiThread(runnable);
+	}
 
+	/**
+	 * Validate an existing token and expiration, and use them for the Facebook
+	 * session, rather than re-authenticating the app (which presents a rather
+	 * user experience in mobile).
+	 *
+	 * @return				true if ok, or print a stack trace
+	 */
+	public void reauthorize(final String appid, JSONArray args) {
+		Log.d("PhoneGapLog", "reauthorize");
+		final FacebookAuth fba = this;
+		final String access_token = args.optString(1, null);
+		final Long expires = args.optLong(2, -1);
+		try {
+			if (fba.mFb == null) {
+				fba.mFb = new Facebook(appid);
+				fba.mFb.setPlugin(fba);
+			}
+			if (access_token != null && expires != -1) {
+				fba.mFb.setAccessToken(access_token);
+				fba.mFb.setAccessExpires(expires);
+			}
+		} catch (JSONException e) {
+			e.printStackTrace();
+		}
+		this.success(new PluginResult(PluginResult.Status.OK, fba.mFb.isSessionValid()), this.callback);
 	}
 
 	class AuthorizeListener implements DialogListener {

Android/Facebook/www/facebook.js

@@ -14,6 +14,10 @@
         PhoneGap.exec(callback, null, "FacebookAuth", "authorize", [app_id]);
     };
 
+    Facebook.prototype.reauthorize = function(app_id, token, expires, callback) {
+        PhoneGap.exec(callback, null, "FacebookAuth", "reauthorize", [app_id, token, expires]);
+    };
+
     Facebook.prototype.setPermissions = function(permissions, callback) {
         PhoneGap.exec(callback, null, "FacebookAuth", "setPermissions", permissions);
     };