Partially implemented view recycling for Slider with note to improve

Summary: Recycling and dealloc were not implemented at all before for Slider, so I've taken a first stab at it. It's a little more complex than I initially thought, due to things I don't 100% understand about UISlider as well as Fabric, so I've left a TODO note to fix this at some point. We should be aware that view recycling doesn't appear to be working the way I would expect currently though.

Reviewed By: shergin

Differential Revision: D13965475

fbshipit-source-id: fd18a219cead770b63b514fdc868e23214e735b7

React/Fabric/Mounting/ComponentViews/Slider/RCTSliderComponentView.mm

@@ -69,6 +69,44 @@ - (instancetype)initWithFrame:(CGRect)frame
   return self;
 }
 
+// Recycling still doesn't work 100% properly
+// TODO: T40099998 implement recycling properly for Fabric Slider component
+- (void)prepareForRecycle
+{
+  [super prepareForRecycle];
+
+  self.trackImageCoordinator = nullptr;
+  self.minimumTrackImageCoordinator = nullptr;
+  self.maximumTrackImageCoordinator = nullptr;
+  self.thumbImageCoordinator = nullptr;
+
+  _sliderLocalData.reset();
+
+  // Tint colors will be taken care of when props are set again - we just
+  // need to make sure that image properties are reset here
+  [_sliderView setMinimumTrackImage:nil forState:UIControlStateNormal];
+  [_sliderView setMaximumTrackImage:nil forState:UIControlStateNormal];
+  [_sliderView setThumbImage:nil forState:UIControlStateNormal];
+
+  _trackImage = nil;
+  _minimumTrackImage = nil;
+  _maximumTrackImage = nil;
+  _thumbImage = nil;
+}
+
+-(void)dealloc
+{
+  self.trackImageCoordinator = nullptr;
+  self.minimumTrackImageCoordinator = nullptr;
+  self.maximumTrackImageCoordinator = nullptr;
+  self.thumbImageCoordinator = nullptr;
+
+  _trackImageResponseObserverProxy.reset();
+  _minimumTrackImageResponseObserverProxy.reset();
+  _maximumTrackImageResponseObserverProxy.reset();
+  _thumbImageResponseObserverProxy.reset();
+}
+
 #pragma mark - RCTComponentViewProtocol
 
 + (ComponentHandle)componentHandle