[Android] Add spellchecking support in android_webview.

android_webview/renderer/aw_content_renderer_client.h

Index: android_webview/renderer/aw_content_renderer_client.h
diff --git a/android_webview/renderer/aw_content_renderer_client.h b/android_webview/renderer/aw_content_renderer_client.h
index 4e2b0aaf94dd0d356c3c87985eabc402536cb2f9..ac0312c85045bccb747cebda8d49196bcce0274c 100644
--- a/android_webview/renderer/aw_content_renderer_client.h
+++ b/android_webview/renderer/aw_content_renderer_client.h
@@ -14,6 +14,11 @@
 #include "components/web_restrictions/interfaces/web_restrictions.mojom.h"
 #include "content/public/renderer/content_renderer_client.h"
 
+#if defined(ENABLE_SPELLCHECK)
+class SpellCheck;
+class SpellCheckProvider;
+#endif
+
 namespace visitedlink {
 class VisitedLinkSlave;
 }
@@ -57,6 +62,10 @@ class AwContentRendererClient : public content::ContentRendererClient {
   std::unique_ptr<visitedlink::VisitedLinkSlave> visited_link_slave_;
   web_restrictions::mojom::WebRestrictionsPtr web_restrictions_service_;
 
+#if defined(ENABLE_SPELLCHECK)
+  std::unique_ptr<SpellCheck> spellcheck_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(AwContentRendererClient);
 };