[PresentationAPI] Use KURL and WebURL in place of string types.

content/renderer/presentation/presentation_connection_client.h

Index: content/renderer/presentation/presentation_connection_client.h
diff --git a/content/renderer/presentation/presentation_connection_client.h b/content/renderer/presentation/presentation_connection_client.h
index a696a8a907ec4556d5aec0ff46078fb21d8bae92..f8e0bac00034b04684557338fcb418b5edb9c314 100644
--- a/content/renderer/presentation/presentation_connection_client.h
+++ b/content/renderer/presentation/presentation_connection_client.h
@@ -25,11 +25,11 @@ class CONTENT_EXPORT PresentationConnectionClient
   ~PresentationConnectionClient() override;
 
   // WebPresentationConnectionClient implementation.
-  blink::WebString getUrl() override;
+  blink::WebURL getUrl() override;
   blink::WebString getId() override;
 
  private:
-  blink::WebString url_;
+  blink::WebURL url_;
   blink::WebString id_;
 };