Clean up globals

Summary: This diff is some boyscouting on cleaning up our globals, and stop using them inconsistently icmw global or window

Reviewed By: aigoncharov

Differential Revision: D33171108

fbshipit-source-id: 400893e5f31523631a7ab6fda428524c751901f1

desktop/flipper-ui-core/src/RenderHost.tsx

@@ -141,8 +141,8 @@ export interface RenderHost {
 }
 
 export function getRenderHostInstance(): RenderHost {
-  if (!window.FlipperRenderHostInstance) {
+  if (!FlipperRenderHostInstance) {
     throw new Error('global FlipperRenderHostInstance was never set');
   }
-  return window.FlipperRenderHostInstance;
+  return FlipperRenderHostInstance;
 }

desktop/flipper-ui-core/src/global.ts

@@ -19,7 +19,5 @@ declare global {
     __REDUX_DEVTOOLS_EXTENSION__:
       | undefined
       | (StoreEnhancerStoreCreator & StoreEnhancerStateSanitizer);
-
-    FlipperRenderHostInstance: RenderHost;
   }
 }