Add support to process favicons from Web Manifests

components/favicon/content/content_favicon_driver.h

Index: components/favicon/content/content_favicon_driver.h
diff --git a/components/favicon/content/content_favicon_driver.h b/components/favicon/content/content_favicon_driver.h
index 4b1b79b65ada76ce315cccc319af3d49c59b7fc2..47ad224395b86c0d7c419f87fa78bf22a041a8f7 100644
--- a/components/favicon/content/content_favicon_driver.h
+++ b/components/favicon/content/content_favicon_driver.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_FAVICON_CONTENT_CONTENT_FAVICON_DRIVER_H_
 
 #include "base/macros.h"
+#include "base/optional.h"
 #include "components/favicon/core/favicon_driver_impl.h"
 #include "content/public/browser/reload_type.h"
 #include "content/public/browser/web_contents_observer.h"
@@ -61,6 +62,8 @@ class ContentFaviconDriver
   int DownloadImage(const GURL& url,
                     int max_image_size,
                     ImageDownloadCallback callback) override;
+  void DownloadManifest(const GURL& url,
+                        ManifestDownloadCallback callback) override;
   bool IsOffTheRecord() override;
   void OnFaviconUpdated(const GURL& page_url,
                         FaviconDriverObserver::NotificationIconType icon_type,
@@ -71,6 +74,8 @@ class ContentFaviconDriver
   // content::WebContentsObserver implementation.
   void DidUpdateFaviconURL(
       const std::vector<content::FaviconURL>& candidates) override;
+  // TODO/DONOTSUBMIT(mastiz): Make this 'override'.
+  void DidUpdateManifestURL(const base::Optional<GURL>& manifest_url);
   void DidStartNavigation(
       content::NavigationHandle* navigation_handle) override;
   void DidFinishNavigation(