Add experimental/pedometer (#1587)

* Add `experimental/pedometer`

* Fixup for linter warnings

* Update CI config

experimental/pedometer/src/pedometerHelper.m

@@ -0,0 +1,38 @@
+#import "pedometerHelper.h"
+#import <CoreMotion/CoreMotion.h>
+#import <CoreMotion/CMPedometer.h>
+#import <Foundation/Foundation.h>
+#import <Foundation/NSDate.h>
+
+#include "dart-sdk/include/dart_api_dl.h"
+
+// Need to import the dart headers to get the definitions Dart_CObject
+#include "dart-sdk/include/dart_api_dl.h"
+
+
+// Helper function that takes a pointer to CMPedometer data and converts it to a Dart C Object
+static Dart_CObject NSObjectToCObject(CMPedometerData* n) {
+  Dart_CObject cobj;
+  cobj.type = Dart_CObject_kInt64;
+  cobj.value.as_int64 = (int64_t) n;
+  return cobj;
+}
+
+
+@implementation PedometerHelper
++(void)startPedometerWithPort: (Dart_Port) sendPort pedometer: (CMPedometer*) pedometer start: (NSDate*) start end: (NSDate*) end {
+    
+  // Start the pedometer
+  [pedometer queryPedometerDataFromDate:start toDate:end withHandler:^(CMPedometerData *pedometerData, NSError *error) {
+    if(error == nil){
+      pedometerData = [pedometerData retain];
+      Dart_CObject data = NSObjectToCObject(pedometerData);
+      const bool success = Dart_PostCObject_DL(sendPort, &data);
+      NSAssert(success, @"Couldn't send to Dart@");
+    }
+    else{
+      NSLog(@"Error:%@", error);
+    }
+  }];
+}
+@end