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..3135dd02185c09ff586dcc99e68b4e2dd636ef6b 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();
+}
+
 }  // namespace
 
 PrefsTabHelper::PrefsTabHelper(WebContents* contents)
@@ -318,10 +331,19 @@ 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.

[gab, 2014/10/02 20:58:42]

Why is this talking about tests in non-test code?

[wjmaclean, 2014/10/03 18:53:22]

It's an explanation of why we cannot assume that there will always be a
|zoom_level_prefs_| available. We routinely put comments about testing in
non-test code (e.g. functions made protected for testing, etc.), so I didn't
think this was inappropriate.

+    if (zoom_level_prefs) {
+      default_zoom_level_subscription_ =
+          zoom_level_prefs->RegisterDefaultZoomLevelCallback(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);
 
@@ -359,11 +381,15 @@ 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,
+  registrar_.Add(this,
+                 chrome::NOTIFICATION_BROWSER_THEME_CHANGED,
                  content::Source<ThemeService>(
                      ThemeServiceFactory::GetForProfile(GetProfile())));
 #endif
@@ -567,8 +593,10 @@ 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();
 }