Allows to render with an OpenGL context inside a TextureView.

Change-Id: I59453f7fc3997f0502a1c5d325d37fed376fabc7
diff --git a/libs/hwui/Layer.h b/libs/hwui/Layer.h
index 16566b8..0310bc3 100644
--- a/libs/hwui/Layer.h
+++ b/libs/hwui/Layer.h
@@ -47,6 +47,7 @@
         meshElementCount = 0;
         isCacheable = true;
         isTextureLayer = false;
+        renderTarget = GL_TEXTURE_2D;
     }
 
     ~Layer() {
@@ -155,6 +156,11 @@
      * Optional texture coordinates transform.
      */
     mat4 texTransform;
+
+    /**
+     * Indicates the render target.
+     */
+    GLenum renderTarget;
 }; // struct Layer
 
 }; // namespace uirenderer