Cherry-pick #12013 into release-boba (#12620)

* [ios] Cherry-pick 12013

* [ios] Updated Changelog.md

* [ios] Fix MBXCustomLocationViewController iOS 8 compatibility.

platform/darwin/src/MGLLocationManager.h

@@ -0,0 +1,181 @@
+#import <Foundation/Foundation.h>
+#import <CoreLocation/CoreLocation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@protocol MGLLocationManagerDelegate;
+
+/**
+ The `MGLLocationManager` protocol defines a set of methods that a class must
+ implement in order to serve as the location manager of an `MGLMapView`. A location
+ manager is responsible for notifying the map view about location-related events,
+ such as a change in the user’s location. This protocol is similar to the
+ Core Location framework’s `CLLocationManager` class, but your implementation
+ does not need to be based on `CLLocationManager`.
+ 
+ */
+@protocol MGLLocationManager <NSObject>
+
+@optional
+
+#pragma mark Configuring Location Update Precision
+
+/**
+ Specifies the minimum distance (measured in meters) a device must move horizontally
+ before a location update is generated.
+ 
+ The default value of this property is `kCLDistanceFilterNone` when `MGLMapView` uses its
+ default location manager.
+ 
+ @see `CLLocationManager.distanceFilter`
+ */
+@property(nonatomic, assign) CLLocationDistance distanceFilter;
+
+/**
+ Specifies the accuracy of the location data.
+ 
+ The default value is `kCLLocationAccuracyBest` when `MGLMapView` uses its
+ default location manager.
+ 
+ @note Determining a location with greater accuracy requires more time and more power.
+ 
+ @see `CLLocationManager.desiredAccuracy`
+ */
+@property (nonatomic, assign) CLLocationAccuracy desiredAccuracy;
+
+/**
+ Specifies the type of user activity associated with the location updates.
+ 
+ The location manager uses this property as a cue to determine when location updates
+ may be automatically paused.
+ 
+ The default value is `CLActivityTypeOther` when `MGLMapView` uses its
+ default location manager.
+ 
+ @see `CLLocationManager.activityType`
+ */
+@property (nonatomic, assign) CLActivityType activityType;
+
+@required
+
+/**
+ The delegate to receive location updates.
+ 
+ Do not set the location manager’s delegate yourself. `MGLMapView` sets this property
+ after the location manager becomes `MGLMapView`’s location manager.
+ */
+@property (nonatomic, weak) id<MGLLocationManagerDelegate> delegate;
+
+#pragma mark Requesting Authorization for Location Services
+
+/**
+ Returns the current localization authorization status.
+ 
+ @see `+[CLLocationManger authorizationStatus]`
+ */
+@property (nonatomic, readonly) CLAuthorizationStatus authorizationStatus;
+
+/**
+ Requests permission to use the location services whenever the app is running.
+ */
+- (void)requestAlwaysAuthorization;
+
+/**
+ Requests permission to use the location services while the app is in
+ the foreground.
+ */
+- (void)requestWhenInUseAuthorization;
+
+#pragma mark Initiating Location Updates
+
+/**
+ Starts the generation of location updates that reports the user's current location.
+ */
+- (void)startUpdatingLocation;
+
+/**
+ Stops the generation of location updates.
+ */
+- (void)stopUpdatingLocation;
+
+#pragma mark Initiating Heading Updates
+
+/**
+ Specifies a physical device orientation.
+ */
+@property (nonatomic) CLDeviceOrientation headingOrientation;
+
+/**
+ Starts the generation of heading updates that reports the user's current hading.
+ */
+- (void)startUpdatingHeading;
+
+/**
+ Stops the generation of heading updates.
+ */
+- (void)stopUpdatingHeading;
+
+/**
+ Dissmisses immediately the heading calibration view from screen.
+ */
+- (void)dismissHeadingCalibrationDisplay;
+
+@end
+
+/**
+ The `MGLLocationManagerDelegate` protocol defines a set of methods that respond
+ to location updates from an `MGLLocationManager` object that is serving as the
+ location manager of an `MGLMapView`.
+ */
+@protocol MGLLocationManagerDelegate <NSObject>
+
+#pragma mark Responding to Location Updates
+
+/**
+ Notifies the delegate with the new location data.
+ 
+ @param manager The location manager reporting the update.
+ @param locations An array of `CLLocation` objects in chronological order,
+ with the last object representing the most recent location. This array
+ contains multiple `CLLocation` objects when `MGLMapView` uses  its
+ default location manager.
+ */
+- (void)locationManager:(id<MGLLocationManager>)manager
+     didUpdateLocations:(NSArray<CLLocation *> *)locations;
+
+#pragma mark Responding to Heading Updates
+
+/**
+ Notifies the delegate with the new heading data.
+ 
+ @param manager The location manager reporting the update.
+ @param newHeading The new heading update.
+ */
+- (void)locationManager:(id<MGLLocationManager>)manager
+       didUpdateHeading:(CLHeading *)newHeading;
+
+/**
+ Asks the delegate if the calibration alert should be displayed.
+ 
+ @param manager The location manager reporting the calibration.
+ */
+- (BOOL)locationManagerShouldDisplayHeadingCalibration:(id<MGLLocationManager>)manager;
+
+#pragma mark Responding to Location Updates Errors
+
+/**
+ Notifies the delegate that the location manager was unable to retrieve
+ location updates.
+ 
+ @param manager The location manager reporting the error.
+ @param error An error object containing the error code that indicates
+ why the location manager failed.
+ */
+- (void)locationManager:(id<MGLLocationManager>)manager
+       didFailWithError:(nonnull NSError *)error;
+
+@optional
+
+@end
+
+NS_ASSUME_NONNULL_END

platform/darwin/src/MGLLocationManager.m

@@ -0,0 +1,116 @@
+#import "MGLLocationManager_Private.h"
+
+@interface MGLCLLocationManager()<CLLocationManagerDelegate>
+
+@property (nonatomic) CLLocationManager *locationManager;
+
+@end
+
+@implementation MGLCLLocationManager
+
+- (instancetype)init
+{
+    if (self = [super init]) {
+        _locationManager = [[CLLocationManager alloc] init];
+        _locationManager.delegate = self;
+    }
+    return self;
+}
+
+@synthesize delegate;
+
+- (void)setHeadingOrientation:(CLDeviceOrientation)headingOrientation
+{
+    self.locationManager.headingOrientation = headingOrientation;
+}
+
+- (CLDeviceOrientation)headingOrientation
+{
+    return self.locationManager.headingOrientation;
+}
+
+- (void)setDesiredAccuracy:(CLLocationAccuracy)desiredAccuracy {
+    self.locationManager.desiredAccuracy = desiredAccuracy;
+}
+
+- (CLLocationAccuracy)desiredAccuracy {
+    return self.locationManager.desiredAccuracy;
+}
+
+- (CLAuthorizationStatus)authorizationStatus {
+    return [CLLocationManager authorizationStatus];
+}
+
+- (void)setActivityType:(CLActivityType)activityType {
+    self.locationManager.activityType = activityType;
+}
+
+- (CLActivityType)activityType {
+    return self.locationManager.activityType;
+}
+
+- (void)dismissHeadingCalibrationDisplay {
+    [self.locationManager dismissHeadingCalibrationDisplay];
+}
+
+- (void)requestAlwaysAuthorization {
+    [self.locationManager requestAlwaysAuthorization];
+}
+
+- (void)requestWhenInUseAuthorization {
+    [self.locationManager requestWhenInUseAuthorization];
+}
+
+- (void)startUpdatingHeading {
+    [self.locationManager startUpdatingHeading];
+}
+
+- (void)startUpdatingLocation {
+    [self.locationManager startUpdatingLocation];
+}
+
+- (void)stopUpdatingHeading {
+    [self.locationManager stopUpdatingHeading];
+}
+
+- (void)stopUpdatingLocation {
+    [self.locationManager stopUpdatingLocation];
+}
+
+- (void)dealloc
+{
+    [self.locationManager stopUpdatingLocation];
+    [self.locationManager stopUpdatingHeading];
+    self.locationManager.delegate = nil;
+    self.delegate = nil;
+}
+
+#pragma mark - CLLocationManagerDelegate
+
+- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations {
+    if ([self.delegate respondsToSelector:@selector(locationManager:didUpdateLocations:)]) {
+        [self.delegate locationManager:self didUpdateLocations:locations];
+    }
+}
+
+- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading {
+    if ([self.delegate respondsToSelector:@selector(locationManager:didUpdateHeading:)]) {
+        [self.delegate locationManager:self didUpdateHeading:newHeading];
+    }
+}
+
+- (BOOL)locationManagerShouldDisplayHeadingCalibration:(CLLocationManager *)manager {
+    if ([self.delegate respondsToSelector:@selector(locationManagerShouldDisplayHeadingCalibration:)]) {
+        return [self.delegate locationManagerShouldDisplayHeadingCalibration:self];
+    }
+
+    return NO;
+}
+
+- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
+    if ([self.delegate respondsToSelector:@selector(locationManager:didFailWithError:)]) {
+        [self.delegate locationManager:self didFailWithError:error];
+    }
+}
+
+@end

platform/darwin/src/MGLLocationManager_Private.h

@@ -0,0 +1,5 @@
+#import "MGLLocationManager.h"
+
+@interface MGLCLLocationManager : NSObject<MGLLocationManager>
+
+@end

platform/ios/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 Mapbox welcomes participation and contributions from everyone. Please read [CONTRIBUTING.md](../../CONTRIBUTING.md) to get started.
 
+## 4.0.5
+
+* Added an `MGLMapView.locationManager` property and `MGLLocationManager` protocol for tracking user location using a custom alternative to `CLLocationManager`. ([#12013](https://github.com/mapbox/mapbox-gl-native/pull/12013))
+
 ## 4.0.4 - June 27, 2018
 
 * Improved compatibility with Mapbox China APIs. ([#12233](https://github.com/mapbox/mapbox-gl-native/pull/12233))

platform/ios/app/MBXCustomLocationViewController.h

@@ -0,0 +1,5 @@
+#import <UIKit/UIKit.h>
+
+@interface MBXCustomLocationViewController : UIViewController
+
+@end