Don't enqueue another UI operation if we're already on the UI thread

Reviewed By: alexeylang

Differential Revision: D5085488

fbshipit-source-id: 0613c1403a67d63ad06ce2db9950d902f1c6473a

Author: aaronechiu

ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java

@@ -105,13 +105,7 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
       mWasMeasured = true;
       // Check if we were waiting for onMeasure to attach the root view.
       if (mReactInstanceManager != null && !mIsAttachedToInstance) {
-        // Enqueue it to UIThread not to block onMeasure waiting for the catalyst instance creation.
-        UiThreadUtil.runOnUiThread(new Runnable() {
-          @Override
-          public void run() {
-            attachToReactInstanceManager();
-          }
-        });
+        attachToReactInstanceManager();
       }
     } finally {
       Systrace.endSection(TRACE_TAG_REACT_JAVA_BRIDGE);