Migrate HostZoomMap to live in StoragePartition.

chrome/browser/ui/prefs/prefs_tab_helper.cc

Index: chrome/browser/ui/prefs/prefs_tab_helper.cc
diff --git a/chrome/browser/ui/prefs/prefs_tab_helper.cc b/chrome/browser/ui/prefs/prefs_tab_helper.cc
index d6406993c49e59d1641e6fee96da83fa4387d8b5..6cc78186a767e48a1cdbcfbaf804a09b0e6294a0 100644
--- a/chrome/browser/ui/prefs/prefs_tab_helper.cc
+++ b/chrome/browser/ui/prefs/prefs_tab_helper.cc
@@ -21,7 +21,9 @@
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
+#include "content/public/browser/storage_partition.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/web_preferences.h"
 #include "grit/locale_settings.h"
@@ -315,13 +317,39 @@ void OverrideFontFamily(WebPreferences* prefs,
 PrefsTabHelper::PrefsTabHelper(WebContents* contents)
     : web_contents_(contents),
       weak_ptr_factory_(this) {
+  // TODO(wjmaclean) Would it be better to plumb a helper function on
+  // RenderProcessHost to simplify this type of call?
+  PrefService* zoom_level_prefs = contents->GetRenderProcessHost()
+                                      ->GetStoragePartition()
+                                      ->GetZoomLevelPrefs();
+  if (zoom_level_prefs) {
+    zoom_level_pref_change_registrar_.Init(zoom_level_prefs);
+    base::Closure renderer_callback = base::Bind(
+        &PrefsTabHelper::UpdateRendererPreferences, base::Unretained(this));
+    zoom_level_pref_change_registrar_.Add(prefs::kDefaultZoomLevel,
+                                          renderer_callback);
+    if (zoom_level_prefs->GetInitializationStatus() ==
+        PrefService::INITIALIZATION_STATUS_WAITING) {
+      // Unlike per-profile prefs, which are guaranteed to have initialized by
+      // the time we get here, zoom-level prefs (per-partition) may not have
+      // completed their initialization. In this case, we need to re-sync the
+      // renderer prefs once their initialization completes so that the default
+      // zoom level information is updated.
+      // TODO(wjmaclean) We need to determine if there are possible lifetime
+      // issues here, namely, can 'this' disappear before the zoom_level_prefs
+      // have finished initializing, causing a stale pointer via the callback?
+      zoom_level_prefs->AddPrefInitObserver(
+          base::Bind(&PrefsTabHelper::UpdateAfterZoomLevelPrefsInitialized,
+                     base::Unretained(this)));
+    }
+  }
+
   PrefService* prefs = GetProfile()->GetPrefs();
   pref_change_registrar_.Init(prefs);
   if (prefs) {
     base::Closure renderer_callback = base::Bind(
         &PrefsTabHelper::UpdateRendererPreferences, base::Unretained(this));
     pref_change_registrar_.Add(prefs::kAcceptLanguages, renderer_callback);
-    pref_change_registrar_.Add(prefs::kDefaultZoomLevel, renderer_callback);
     pref_change_registrar_.Add(prefs::kEnableDoNotTrack, renderer_callback);
     pref_change_registrar_.Add(prefs::kEnableReferrers, renderer_callback);
 
@@ -566,6 +594,11 @@ void PrefsTabHelper::UpdateWebPreferences() {
       web_contents_->GetRenderViewHost()->GetWebkitPreferences());
 }
 
+void PrefsTabHelper::UpdateAfterZoomLevelPrefsInitialized(bool success) {
+  if (success)
+    UpdateRendererPreferences();
+}
+
 void PrefsTabHelper::UpdateRendererPreferences() {
   renderer_preferences_util::UpdateFromSystemSettings(
       web_contents_->GetMutableRendererPrefs(), GetProfile());