Migrate HostZoomMap to live in StoragePartition.

chrome/browser/ui/toolbar/wrench_menu_model.cc

Index: chrome/browser/ui/toolbar/wrench_menu_model.cc
diff --git a/chrome/browser/ui/toolbar/wrench_menu_model.cc b/chrome/browser/ui/toolbar/wrench_menu_model.cc
index f3b37f410f2b98865d02b91b0ea01922f5dd8419..8314a45d6219dffdf6976979a1ea633ceea39001 100644
--- a/chrome/browser/ui/toolbar/wrench_menu_model.cc
+++ b/chrome/browser/ui/toolbar/wrench_menu_model.cc
@@ -78,7 +78,6 @@
 #endif
 
 using base::UserMetricsAction;
-using content::HostZoomMap;
 using content::WebContents;
 
 namespace {
@@ -285,10 +284,13 @@ WrenchMenuModel::WrenchMenuModel(ui::AcceleratorProvider* provider,
   Build();
   UpdateZoomControls();
 
-  content_zoom_subscription_ = content::HostZoomMap::GetForBrowserContext(
-      browser->profile())->AddZoomLevelChangedCallback(
-          base::Bind(&WrenchMenuModel::OnZoomLevelChanged,
-                     base::Unretained(this)));
+  // By asking for the HostZoomMap via the BrowserContext, we get the map
+  // associated with the default storage partition, and not the one related
+  // to any specialized storage partitions, e.g. those used by WebViewGuests.
+  content_zoom_subscription_ =
+      content::HostZoomMap::GetDefaultForBrowserContext(browser->profile())
+          ->AddZoomLevelChangedCallback(base::Bind(
+              &WrenchMenuModel::OnZoomLevelChanged, base::Unretained(this)));
 
   browser_zoom_subscription_ = ZoomEventManager::GetForBrowserContext(
       browser->profile())->AddZoomLevelChangedCallback(