Introduce ChromeZoomLevelPref, make zoom level prefs independent of profile prefs.

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 816e08b60f60092d0f97371f9dc9d6261dbc86bb..ad2d5b887e4896640fb0b4f15dee246b6b819c22 100644
--- a/chrome/browser/ui/prefs/prefs_tab_helper.cc
+++ b/chrome/browser/ui/prefs/prefs_tab_helper.cc
@@ -15,15 +15,19 @@
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_preferences_util.h"
+#include "chrome/browser/ui/zoom/chrome_zoom_level_prefs.h"
+#include "chrome/browser/ui/zoom/zoom_controller.h"
 #include "chrome/common/pref_font_webkit_names.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/pref_names_util.h"
 #include "chrome/grit/locale_settings.h"
 #include "components/pref_registry/pref_registry_syncable.h"
+#include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/renderer_preferences.h"
 #include "content/public/common/web_preferences.h"
 #include "grit/platform_locale_settings.h"
 #include "third_party/icu/source/common/unicode/uchar.h"
@@ -310,6 +314,15 @@ void OverrideFontFamily(WebPreferences* prefs,
   (*map)[script] = base::UTF8ToUTF16(pref_value);
 }
 
+double GetDefaultZoomLevel(const content::WebContents* web_contents) {
+  const ZoomController* zoom_controller =
+      ZoomController::FromWebContents(web_contents);
+  if (zoom_controller)
+    return zoom_controller->GetDefaultZoomLevel();
+  return content::HostZoomMap::GetDefaultForBrowserContext(
+             web_contents->GetBrowserContext())->GetDefaultZoomLevel();

[Bernhard Bauer, 2014/10/01 15:09:14]

Align this just four spaces w/r/t the previous line.

[wjmaclean, 2014/10/01 20:33:00]

Done.

+}
+
 }  // namespace
 
 PrefsTabHelper::PrefsTabHelper(WebContents* contents)
@@ -318,10 +331,20 @@ PrefsTabHelper::PrefsTabHelper(WebContents* contents)
   PrefService* prefs = GetProfile()->GetPrefs();
   pref_change_registrar_.Init(prefs);
   if (prefs) {
+    // TODO(wjmaclean): Convert this to use the content-specific zoom-level
+    // prefs when HostZoomMap moves to StoragePartition.
+    chrome::ChromeZoomLevelPrefs* zoom_level_prefs =
+        GetProfile()->GetZoomLevelPrefs();
+
     base::Closure renderer_callback = base::Bind(
         &PrefsTabHelper::UpdateRendererPreferences, base::Unretained(this));
+    // Not all tests will create zoom_level_prefs.
+    if (zoom_level_prefs) {
+      pref_change_registrar_.Add(
+          zoom_level_prefs->GetDefaultZoomLevelPath().c_str(),

[Bernhard Bauer, 2014/10/01 15:09:14]

Hm, this is problematic. Like I said above you can't register keys that are
prefixes of other keys (or at least you can't rely on the fact that they share
subdictionaries), but that means you can't easily observe changes. You might
have to watch for changes to the top-level dictionary.

[wjmaclean, 2014/10/01 20:33:00]

As per our off-line discussion, this means I will have to force *all* access to
this parameter to go through ChromeZoomLevelPrefs so it can manage notifications
for any interested clients.

+          renderer_callback);
+    }
     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);
 
@@ -359,13 +382,18 @@ PrefsTabHelper::PrefsTabHelper(WebContents* contents)
                                   webkit_callback);
   }
 
-  renderer_preferences_util::UpdateFromSystemSettings(
-      web_contents_->GetMutableRendererPrefs(), GetProfile());
+  content::RendererPreferences* render_prefs =
+      web_contents_->GetMutableRendererPrefs();
+  renderer_preferences_util::UpdateFromSystemSettings(render_prefs,
+                                                      GetProfile());
+  render_prefs->default_zoom_level = GetDefaultZoomLevel(web_contents_);
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && defined(ENABLE_THEMES)
-  registrar_.Add(this, chrome::NOTIFICATION_BROWSER_THEME_CHANGED,
-                 content::Source<ThemeService>(
-                     ThemeServiceFactory::GetForProfile(GetProfile())));
+            registrar_.Add(

[Bernhard Bauer, 2014/10/01 15:09:14]

Indent is off here.

[wjmaclean, 2014/10/01 20:33:00]

Done.

+                this,
+                chrome::NOTIFICATION_BROWSER_THEME_CHANGED,
+                content::Source<ThemeService>(
+                    ThemeServiceFactory::GetForProfile(GetProfile())));
 #endif
 #if defined(USE_AURA)
   registrar_.Add(this,
@@ -567,8 +595,10 @@ void PrefsTabHelper::UpdateWebPreferences() {
 }
 
 void PrefsTabHelper::UpdateRendererPreferences() {
-  renderer_preferences_util::UpdateFromSystemSettings(
-      web_contents_->GetMutableRendererPrefs(), GetProfile());
+  content::RendererPreferences* prefs =
+      web_contents_->GetMutableRendererPrefs();
+  renderer_preferences_util::UpdateFromSystemSettings(prefs, GetProfile());
+  prefs->default_zoom_level = GetDefaultZoomLevel(web_contents_);
   web_contents_->GetRenderViewHost()->SyncRendererPrefs();
 }