Add mojo service for CopylessPaste in Blink

third_party/WebKit/public/platform/modules/document_metadata/copyless_paste.mojom

Index: third_party/WebKit/public/platform/modules/document_metadata/copyless_paste.mojom
diff --git a/third_party/WebKit/public/platform/modules/document_metadata/copyless_paste.mojom b/third_party/WebKit/public/platform/modules/document_metadata/copyless_paste.mojom
index 028d6eb2152184d4ce858cc52aa2b798ee7f0909..7fcaff5097bee96d874b5d0f9bae95fac65e902d 100644
--- a/third_party/WebKit/public/platform/modules/document_metadata/copyless_paste.mojom
+++ b/third_party/WebKit/public/platform/modules/document_metadata/copyless_paste.mojom
@@ -34,3 +34,8 @@ struct WebPage {
   string title;
   array<Entity> entities;
 };
+
+// Null page denotes no results.
+interface CopylessPaste {
+  GetEntities() => (WebPage? page);
+};