Animations: attempt to mitigate crashes in T43628589

Summary: Trying to mitigate animation-related crashes in T43628589. Clues: all the crashes are off the main thread, and most operations in this class happen explicitly in blocks executed on the main thread. I think there's a category of race conditions caused by animations not being allocated yet when this code runs / being deallocated as it's running. We shouldn't need to add locks if everything just runs on the main thread.

Reviewed By: PeteTheHeat

Differential Revision: D15924310

fbshipit-source-id: d82f5434e53fd394c4a7548d52f59a0f63961779

Author: JoshuaGross

Libraries/NativeAnimation/RCTNativeAnimatedModule.m

@@ -87,10 +87,14 @@ - (void)setBridge:(RCTBridge *)bridge
   [self addOperationBlock:^(RCTNativeAnimatedNodesManager *nodesManager) {
     [nodesManager startAnimatingNode:animationId nodeTag:nodeTag config:config endCallback:callBack];
   }];
-  if ([_nodesManager isNodeManagedByFabric:nodeTag]) {
-    _animIdIsManagedByFabric[animationId] = @YES;
-    [self flushOperationQueues];
-  }
+  __weak RCTNativeAnimatedModule *weakSelf = self;
+  RCTExecuteOnMainQueue(^{
+      __strong RCTNativeAnimatedModule *strongSelf = weakSelf;
+      if (strongSelf && [strongSelf->_nodesManager isNodeManagedByFabric:nodeTag]) {
+          strongSelf->_animIdIsManagedByFabric[animationId] = @YES;
+          [strongSelf flushOperationQueues];
+      }
+  });
 }
 
 RCT_EXPORT_METHOD(stopAnimation:(nonnull NSNumber *)animationId)

Libraries/NativeAnimation/RCTNativeAnimatedNodesManager.m

@@ -53,7 +53,10 @@ - (instancetype)initWithBridge:(nonnull RCTBridge *)bridge
 - (BOOL)isNodeManagedByFabric:(nonnull NSNumber *)tag
 {
   RCTAnimatedNode *node = _animationNodes[tag];
-  return [node isManagedByFabric];
+  if (node) {
+    return [node isManagedByFabric];
+  }
+  return false;
 }
 
 #pragma mark -- Graph