Checks if the MountState will remount with the RenderTree before calling before mount

Summary: Checks if the MountState will remount with a given RenderTree before calling before mount in Litho

Reviewed By: pentiumao

Differential Revision: D75218907

fbshipit-source-id: ca9550a388306d36fa2ed437b19e1f1f5be729d1

Author: adityasharat

litho-core/src/main/java/com/facebook/litho/BaseMountingView.kt

@@ -499,7 +499,9 @@ constructor(context: ComponentContext, attrs: AttributeSet? = null) :
       val renderTree = layoutState.toRenderTree()
       setupMountExtensions()
       val coordinator = requireNotNull(lithoHostListenerCoordinator)
-      coordinator.beforeMount(layoutState, visibleRect)
+      if (mountState.willRemountWith(renderTree)) {
+        coordinator.beforeMount(layoutState, visibleRect)
+      }
       mountState.mount(renderTree)
       incrementComponentMountCount()
       drawDebugOverlay(this, layoutState.componentTreeId)

litho-rendercore/src/main/java/com/facebook/rendercore/MountState.kt

@@ -404,10 +404,14 @@ constructor(
     }
   }
 
+  fun willRemountWith(renderTree: RenderTree): Boolean {
+    return this.renderTree != renderTree || _needsRemount
+  }
+
   /** Updates the extensions of this [MountState] from the new [RenderTree]. */
   private fun updateRenderTree(renderTree: RenderTree): Boolean {
     // If the trees are same or if no remount is required, then no update is required.
-    if (renderTree == this.renderTree && !_needsRemount) {
+    if (!willRemountWith(renderTree)) {
       return false
     }