RCTVirtualText wasn't clickable in certain cases

Summary:
Text in Nodes is squashed into a single DrawCommand for drawing a
Boring or StaticLayout. Touch is handled using a TextNodeRegion subclass of
NodeRegion that knows how to identify pieces of text inside of the DrawCommand
based on spans in the text. However, we only use a TextNodeRegion on the
second call for updateNodeRegion for an RCTText. If there is only one call,
the NodeRegion will just be a normal one. This patch ensures that the
NodeRegion for an RCTText is always a TextNodeRegion, allowing for null
Layouts that are set when the DrawCommand is made.

Reviewed By: astreet

Differential Revision: D3291682

ReactAndroid/src/main/java/com/facebook/react/flat/RCTText.java

@@ -179,6 +179,7 @@ protected void collectState(
       return;
     }
 
+    boolean updateNodeRegion = false;
     if (mDrawCommand == null) {
       // Layout was not created during the measure pass, must be Boring, create it now
       mDrawCommand = new DrawTextLayout(new BoringLayout(
@@ -190,6 +191,7 @@ protected void collectState(
           mSpacingAdd,
           mBoringLayoutMetrics,
           INCLUDE_PADDING));
+      updateNodeRegion = true;
     }
 
     Spacing padding = getPadding();
@@ -212,6 +214,13 @@ protected void collectState(
         clipBottom);
     stateBuilder.addDrawCommand(mDrawCommand);
 
+    if (updateNodeRegion) {
+      NodeRegion nodeRegion = getNodeRegion();
+      if (nodeRegion instanceof TextNodeRegion) {
+        ((TextNodeRegion) nodeRegion).setLayout(mDrawCommand.getLayout());
+      }
+    }
+
     performCollectAttachDetachListeners(stateBuilder);
   }
 
@@ -240,12 +249,16 @@ public void setNumberOfLines(int numberOfLines) {
       float right,
       float bottom,
       boolean isVirtual) {
+
+    NodeRegion nodeRegion = getNodeRegion();
     if (mDrawCommand == null) {
-      super.updateNodeRegion(left, top, right, bottom, isVirtual);
+      if (nodeRegion.mLeft != left || nodeRegion.mTop != top || nodeRegion.mRight != right ||
+          nodeRegion.mBottom != bottom || nodeRegion.mIsVirtual != isVirtual) {
+        setNodeRegion(new TextNodeRegion(left, top, right, bottom, getReactTag(), isVirtual, null));
+      }
       return;
     }
 
-    NodeRegion nodeRegion = getNodeRegion();
     Layout layout = null;
 
     if (nodeRegion instanceof TextNodeRegion) {

ReactAndroid/src/main/java/com/facebook/react/flat/TextNodeRegion.java

@@ -9,11 +9,13 @@
 
 package com.facebook.react.flat;
 
+import javax.annotation.Nullable;
+
 import android.text.Layout;
 import android.text.Spanned;
 
 /* package */ final class TextNodeRegion extends NodeRegion {
-  private final Layout mLayout;
+  private @Nullable Layout mLayout;
 
   /* package */ TextNodeRegion(
       float left,
@@ -22,29 +24,35 @@
       float bottom,
       int tag,
       boolean isVirtual,
-      Layout layout) {
+      @Nullable Layout layout) {
     super(left, top, right, bottom, tag, isVirtual);
     mLayout = layout;
   }
 
-  /* package */ Layout getLayout() {
+  public void setLayout(Layout layout) {
+    mLayout = layout;
+  }
+
+  /* package */ @Nullable Layout getLayout() {
     return mLayout;
   }
 
   /* package */ int getReactTag(float touchX, float touchY) {
-    int y = Math.round(touchY - mTop);
-    if (y >= mLayout.getLineTop(0) && y < mLayout.getLineBottom(mLayout.getLineCount() - 1)) {
-      float x = Math.round(touchX - mLeft);
-      int line = mLayout.getLineForVertical(y);
+    if (mLayout != null) {
+      int y = Math.round(touchY - mTop);
+      if (y >= mLayout.getLineTop(0) && y < mLayout.getLineBottom(mLayout.getLineCount() - 1)) {
+        float x = Math.round(touchX - mLeft);
+        int line = mLayout.getLineForVertical(y);
 
-      if (mLayout.getLineLeft(line) <= x && x <= mLayout.getLineRight(line)) {
-        int off = mLayout.getOffsetForHorizontal(line, x);
+        if (mLayout.getLineLeft(line) <= x && x <= mLayout.getLineRight(line)) {
+          int off = mLayout.getOffsetForHorizontal(line, x);
 
-        Spanned text = (Spanned) mLayout.getText();
-        RCTRawText[] link = text.getSpans(off, off, RCTRawText.class);
+          Spanned text = (Spanned) mLayout.getText();
+          RCTRawText[] link = text.getSpans(off, off, RCTRawText.class);
 
-        if (link.length != 0) {
-          return link[0].getReactTag();
+          if (link.length != 0) {
+            return link[0].getReactTag();
+          }
         }
       }
     }