RCTImagePicker now uses main thread

Summary: public

RCTImagePicker (aka ImagePickerIOS) was previously displaying UI from a random thread, which is unsafe. This diff forces it to execute on the main thread instead.

Reviewed By: jspahrsummers

Differential Revision: D2657465

fb-gh-sync-id: 3c0fa6935061ccaa3e6ce649b4e3e8ad8c701384

Libraries/CameraRoll/RCTImagePickerManager.m

@@ -42,6 +42,11 @@ RCT_EXPORT_MODULE(ImagePickerIOS);
   return self;
 }
 
+- (dispatch_queue_t)methodQueue
+{
+  return dispatch_get_main_queue();
+}
+
 RCT_EXPORT_METHOD(canRecordVideos:(RCTResponseSenderBlock)callback)
 {
   NSArray<NSString *> *availableMediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];

Libraries/RCTTest/RCTSnapshotManager.m

@@ -37,7 +37,8 @@
 
 RCT_EXPORT_MODULE()
 
-- (UIView *)view {
+- (UIView *)view
+{
   return [RCTSnapshotView new];
 }