Move ZoomController out of ChromeWebViewGuestDelegate.

extensions/browser/guest_view/guest_view_base.h

Index: extensions/browser/guest_view/guest_view_base.h
diff --git a/extensions/browser/guest_view/guest_view_base.h b/extensions/browser/guest_view/guest_view_base.h
index 52e764803162c5ffc0a2aa47b270dfc84aa357db..d7f68125a0cffbcb08d7851a3a3380134a0df42d 100644
--- a/extensions/browser/guest_view/guest_view_base.h
+++ b/extensions/browser/guest_view/guest_view_base.h
@@ -9,6 +9,7 @@
 
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
+#include "components/ui/zoom/zoom_observer.h"
 #include "content/public/browser/browser_plugin_guest_delegate.h"
 #include "content/public/browser/render_process_host_observer.h"
 #include "content/public/browser/web_contents.h"
@@ -28,7 +29,8 @@ namespace extensions {
 // it is attached to a container within the owner's WebContents.
 class GuestViewBase : public content::BrowserPluginGuestDelegate,
                       public content::WebContentsDelegate,
-                      public content::WebContentsObserver {
+                      public content::WebContentsObserver,
+                      public ui_zoom::ZoomObserver {
  public:
   class Event {
    public:
@@ -249,6 +251,10 @@ class GuestViewBase : public content::BrowserPluginGuestDelegate,
                   int browser_plugin_instance_id,
                   bool is_full_page_plugin) final;
 
+  // ui_zoom::ZoomObserver implementation.
+  void OnZoomChanged(
+      const ui_zoom::ZoomController::ZoomChangedEventData& data) override;
+
   // Dispatches an event |event_name| to the embedder with the |event| fields.
   void DispatchEventToEmbedder(Event* event);
 
@@ -270,6 +276,8 @@ class GuestViewBase : public content::BrowserPluginGuestDelegate,
                     const WebContentsCreatedCallback& callback,
                     content::WebContents* guest_web_contents);
 
+  void OwnerWebContentsWillBeDestroyed();
+
   static void RegisterGuestViewTypes();
 
   // WebContentsObserver implementation.