aw: Add empty functor detach callback

android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java

Index: android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java
diff --git a/android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java b/android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java
index c5a1f3d11811c664799d9ab73047922c7b13711f..380792205e76fd475cf37c01d9cbfe4903d5a2c8 100644
--- a/android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java
+++ b/android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java
@@ -1889,6 +1889,9 @@ class WebViewChromium implements WebViewProvider, WebViewProvider.ScrollDelegate
             return;
         }
 
+        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M && !"N".equals(Build.VERSION.CODENAME)) {
+            mAwContents.onDrawGLFunctorDetached();
+        }
         mAwContents.onDetachedFromWindow();
     }