add upgrading 2x - 3 doc (#226)

* add upgrading 2x - 3 doc

* proper versions

README.md

@@ -13,6 +13,7 @@ Lost operates by making calls directly to the [LocationManger][1]. Lost can run
 Set up:
 - [Installation](https://github.com/mapzen/lost/blob/master/docs/installation.md)
 - [Upgrading 1.x to 2.0](https://github.com/mapzen/lost/blob/master/docs/upgrade-1x-2.md)
+- [Upgrading 2.x to 3.0](https://github.com/mapzen/lost/blob/master/docs/upgrade-2x-3.md)
 - [Getting Started](https://github.com/mapzen/lost/blob/master/docs/getting-started.md)
 - [Getting the Last Known Location](https://github.com/mapzen/lost/blob/master/docs/last-known-location.md)
 - [Receiving Location Updates](https://github.com/mapzen/lost/blob/master/docs/location-updates.md)

docs/upgrade-2x-3.md

@@ -0,0 +1,128 @@
+# Upgrading from Lost 2.x
+
+### Explicitly Unregister Location Updates
+`LocationRequest`s are no longer automatically removed when a client disconnects, therefore you should ensure that you unregister all requests registered:
+
+2.x
+```
+// onConnected
+
+LocationServices.FusedLocationApi.requestLocationUpdates(client, locationRequest, listener);
+
+client.disconnect();
+```
+
+3.x
+```
+// onConnected
+
+LocationServices.FusedLocationApi.requestLocationUpdates(client, locationRequest, listener);
+
+// when disconnecting and shutting down client
+LocationServices.FusedLocationApi.removeLocationUpdates(client, listener); // NOW REQUIRED
+
+client.disconnect();
+```
+
+### Remove Deprecated Methods
+`onProviderDisabled` and `onProviderEnabled` have been removed from `LocationListener`:
+
+2.x
+```
+LocationListener listener = new LocationListener() {
+    @Override public void onLocationChanged(Location location) {
+
+    }
+
+    @Override public void onProviderDisabled(Location location) {
+
+    }
+
+    @Override public void onProviderEnabled(Location location) {
+
+    }
+  };
+```
+
+3.x
+```
+LocationListener listener = new LocationListener() {
+    @Override public void onLocationChanged(Location location) {
+
+    }
+  };
+```
+
+`isProviderEnabled` has been removed from `FusedLocationProviderApi` in favor of `SettingsApi#checkLocationSettings(LostApiClient, LocationSettingsRequest)`
+
+2.x
+```
+boolean enabled = LocationServices.FusedLocationProviderApi.isProviderEnabled(client, GPS_PROVIDER);
+```
+
+3.x
+```
+PendingResult<LocationSettingsResult> result = LocationServices.SettingsApi.checkLocationSettings(apiClient, request);
+
+LocationSettingsResult locationSettingsResult = result.await();
+
+LocationSettingsStates states = locationSettingsResult.getLocationSettingsStates();
+
+boolean enabled = states.isGpsUsable();
+```
+
+### Ensure Application Process
+
+The underlying Lost `Service` now runs in it's own process. Because of this, `Application` subclasses will receive two calls to `onCreate`(https://developer.android.com/reference/android/app/Application.html#onCreate()). To ensure unnecessary initialization isn't done, you should use the current `Context` to determine if `onCreate` is being called for the `Service` and if so, handle flow accordingly.
+
+LeakCanary(https://github.com/square/leakcanary) uses this method:
+
+```
+public static boolean isInServiceProcess(Context context, Class<? extends Service> serviceClass) {
+    PackageManager packageManager = context.getPackageManager();
+    PackageInfo packageInfo;
+    try {
+      packageInfo = packageManager.getPackageInfo(context.getPackageName(), GET_SERVICES);
+    } catch (Exception e) {
+      CanaryLog.d(e, "Could not get package info for %s", context.getPackageName());
+      return false;
+    }
+    String mainProcess = packageInfo.applicationInfo.processName;
+
+    ComponentName component = new ComponentName(context, serviceClass);
+    ServiceInfo serviceInfo;
+    try {
+      serviceInfo = packageManager.getServiceInfo(component, 0);
+    } catch (PackageManager.NameNotFoundException ignored) {
+      // Service is disabled.
+      return false;
+    }
+
+    if (serviceInfo.processName.equals(mainProcess)) {
+      CanaryLog.d("Did not expect service %s to run in main process %s", serviceClass, mainProcess);
+      // Technically we are in the service process, but we're not in the service dedicated process.
+      return false;
+    }
+
+    int myPid = android.os.Process.myPid();
+    ActivityManager activityManager =
+        (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
+    ActivityManager.RunningAppProcessInfo myProcess = null;
+    List<ActivityManager.RunningAppProcessInfo> runningProcesses =
+        activityManager.getRunningAppProcesses();
+    if (runningProcesses != null) {
+      for (ActivityManager.RunningAppProcessInfo process : runningProcesses) {
+        if (process.pid == myPid) {
+          myProcess = process;
+          break;
+        }
+      }
+    }
+    if (myProcess == null) {
+      CanaryLog.d("Could not find running process for %d", myPid);
+      return false;
+    }
+
+    return myProcess.processName.equals(serviceInfo.processName);
+  }
+```