Initialize RootView size to the display size

Summary:
Inits RootView to display size for the early surface start experiment.

Before that experiment, we always had the view measured before the surface was initialized, but here layout can sometimes happen before measure. Surface defaults use [0; Inf) for size constraints, potentially causing a crash in Yoga. This change avoids that by making a guess on default layout size with `displayMetrics`

Changelog: [Internal]

Reviewed By: feedthejim

Differential Revision: D33190397

fbshipit-source-id: 3b1b84135a4980ef2fde4024ec84a448199e00b8

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

@@ -19,6 +19,7 @@ import android.graphics.Rect;
 import android.os.Build;
 import android.os.Bundle;
 import android.util.AttributeSet;
+import android.util.DisplayMetrics;
 import android.view.DisplayCutout;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
@@ -443,6 +444,11 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
       // if in this experiment, we initialize the root earlier in startReactApplication
       // instead of waiting for the initial measure
       if (ReactFeatureFlags.enableEagerRootViewAttachment) {
+        if (!mWasMeasured) {
+          // Ideally, those values will be used by default, but we only update them here to scope
+          // this change to `enableEagerRootViewAttachment` experiment.
+          setSurfaceConstraintsToScreenSize();
+        }
         attachToReactInstanceManager();
       }
     } finally {
@@ -450,6 +456,14 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
     }
   }
 
+  private void setSurfaceConstraintsToScreenSize() {
+    DisplayMetrics displayMetrics = getContext().getResources().getDisplayMetrics();
+    mWidthMeasureSpec =
+        MeasureSpec.makeMeasureSpec(displayMetrics.widthPixels, MeasureSpec.AT_MOST);
+    mHeightMeasureSpec =
+        MeasureSpec.makeMeasureSpec(displayMetrics.heightPixels, MeasureSpec.AT_MOST);
+  }
+
   @Override
   public int getWidthMeasureSpec() {
     return mWidthMeasureSpec;