<webview>: Zooming the embedder should zoom the guest by the same level.

chrome/browser/guest_view/web_view/chrome_web_view_guest_delegate.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 #include "chrome/browser/guest_view/web_view/chrome_web_view_guest_delegate.h"
 
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/favicon/favicon_tab_helper.h"
 #include "chrome/browser/renderer_context_menu/render_view_context_menu.h"
@@ skipping 105 matching lines @@
       content::BrowserThread::IO,
       FROM_HERE,
       base::Bind(
           &RemoveWebViewEventListenersOnIOThread,
           web_view_guest()->browser_context(),
           web_view_guest()->embedder_extension_id(),
           web_view_guest()->embedder_render_process_id(),
           web_view_guest()->view_instance_id()));
 }
 
+void ChromeWebViewGuestDelegate::OnDidAttachToEmbedder() {
+  // TODO(fsamuel): This code should be implemented in GuestViewBase once the
+  // ZoomController moves to the extensions module.
+  ZoomController* zoom_controller = ZoomController::FromWebContents(
+      web_view_guest()->embedder_web_contents());
+  if (!zoom_controller)
+    return;
+  // Listen to the embedder's zoom changes.
+  zoom_controller->AddObserver(this);
+  // Set the guest's initial zoom level to be equal to the embedder's.
+  ZoomController::FromWebContents(guest_web_contents())->
+      SetZoomLevel(zoom_controller->GetZoomLevel());
+}
+
 void ChromeWebViewGuestDelegate::OnDidCommitProvisionalLoadForFrame(
     bool is_main_frame) {
   // Update the current zoom factor for the new page.
   ZoomController* zoom_controller =
       ZoomController::FromWebContents(guest_web_contents());
   DCHECK(zoom_controller);
   current_zoom_factor_ = zoom_controller->GetZoomLevel();
   if (is_main_frame)
     chromevox_injected_ = false;
 }
@@ skipping 95 matching lines @@
     accessibility_subscription_.reset();
   } else if (details.notification_type ==
       chromeos::ACCESSIBILITY_TOGGLE_SPOKEN_FEEDBACK) {
     if (details.enabled)
       InjectChromeVoxIfNeeded(guest_web_contents()->GetRenderViewHost());
     else
       chromevox_injected_ = false;
   }
 }
 #endif
+
+void ChromeWebViewGuestDelegate::OnZoomChanged(
+    const ZoomController::ZoomChangedEventData& data) {
+  ZoomController::FromWebContents(guest_web_contents())->
+      SetZoomLevel(data.new_zoom_level);
+}