[Android] Add spellchecking support in android_webview.

android_webview/native/BUILD.gn

Index: android_webview/native/BUILD.gn
diff --git a/android_webview/native/BUILD.gn b/android_webview/native/BUILD.gn
index 6f22f2c4063ac33d0fca743904db143ce2373e46..5aa8196dc448658c3bfaabba8e3886fc95aac1ec 100644
--- a/android_webview/native/BUILD.gn
+++ b/android_webview/native/BUILD.gn
@@ -118,6 +118,10 @@ source_set("native") {
     deps += [ "//components/external_video_surface:external_video_surface" ]
   }
 
+  if (enable_spellcheck) {
+    deps += [ "//components/spellcheck/browser:browser" ]
+  }
+
   libs = [ "jnigraphics" ]
 }