Remove usage of HostZoomMap from c/b/loader via ReadyToCommitNavigation

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index c9e3649b0621769ed721702b16df5913fc23d2ab..53b04ae02c6a0fba445f5ab66b99a0e1967f8c4e 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -61,6 +61,7 @@ class BrowserPluginGuest;
 class DateTimeChooserAndroid;
 class DownloadItem;
 class FindRequestManager;
+class HostZoomMapObserver;
 class InterstitialPageImpl;
 class JavaScriptDialogManager;
 class LoaderIOThreadNotifier;
@@ -1417,6 +1418,8 @@ class CONTENT_EXPORT WebContentsImpl
   std::unique_ptr<PepperPlaybackObserver> pepper_playback_observer_;
 #endif  // defined(ENABLE_PLUGINS)
 
+  std::unique_ptr<HostZoomMapObserver> host_zoom_map_observer_;
+
   std::unique_ptr<RenderWidgetHostInputEventRouter> rwh_input_event_router_;
 
   PageImportanceSignals page_importance_signals_;