Add setting to isolate zoom changes by default.

chrome/browser/ui/webui/options/content_settings_handler.cc

Index: chrome/browser/ui/webui/options/content_settings_handler.cc
diff --git a/chrome/browser/ui/webui/options/content_settings_handler.cc b/chrome/browser/ui/webui/options/content_settings_handler.cc
index e98857f9c9c0bdb8713ba965e5d94a789072759b..b812caa0405ea05fa9550037e07b6fb10e8bc64b 100644
--- a/chrome/browser/ui/webui/options/content_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/content_settings_handler.cc
@@ -480,6 +480,7 @@ void ContentSettingsHandler::GetLocalizedValues(
     // Zoom levels.
     {"zoomlevelsHeader", IDS_ZOOMLEVELS_HEADER_AND_TAB_LABEL},
     {"zoomLevelsManage", IDS_ZOOMLEVELS_MANAGE_BUTTON},
+    {"zoomLevelsIgnoredExplanation", IDS_ZOOMLEVELS_IGNORED_LABEL},
     // PDF Plugin filter.
     {"pdfTabLabel", IDS_PDF_TAB_LABEL},
     {"pdfEnable", IDS_PDF_ENABLE_CHECKBOX},
@@ -612,9 +613,18 @@ void ContentSettingsHandler::InitializeHandler() {
               base::Bind(&ContentSettingsHandler::OnZoomLevelChanged,
                          base::Unretained(this)));
 
+  Profile* profile = Profile::FromWebUI(web_ui());
+
+  ChromeZoomLevelPrefs* zoom_level_prefs = profile->GetZoomLevelPrefs();
+  if (zoom_level_prefs) {
+    default_zoom_scope_subscription_ =
+        zoom_level_prefs->RegisterDefaultZoomScopeCallback(
+            base::Bind(&ContentSettingsHandler::OnZoomScopeChanged,
+                       base::Unretained(this)));
+  }
+
   flash_settings_manager_.reset(new PepperFlashSettingsManager(this, context));
 
-  Profile* profile = Profile::FromWebUI(web_ui());
   observer_.Add(HostContentSettingsMapFactory::GetForProfile(profile));
   if (profile->HasOffTheRecordProfile()) {
     auto* map = HostContentSettingsMapFactory::GetForProfile(
@@ -632,6 +642,7 @@ void ContentSettingsHandler::InitializePage() {
   UpdateAllExceptionsViewsFromModel();
   UpdateAllChooserExceptionsViewsFromModel();
   UpdateProtectedContentExceptionsButton();
+  UpdateZoomScopeExplanationVisibility();
 }
 
 void ContentSettingsHandler::OnContentSettingChanged(
@@ -1404,6 +1415,10 @@ void ContentSettingsHandler::OnZoomLevelChanged(
   UpdateZoomLevelsExceptionsView();
 }
 
+void ContentSettingsHandler::OnZoomScopeChanged() {
+  UpdateZoomScopeExplanationVisibility();
+}
+
 void ContentSettingsHandler::ShowFlashMediaLink(
     LinkType link_type, ContentSettingsType content_type, bool show) {
   MediaSettingsInfo::ForOneType& settings =
@@ -1497,4 +1512,16 @@ void ContentSettingsHandler::UpdateProtectedContentExceptionsButton() {
       base::FundamentalValue(enable_exceptions));
 }
 
+void ContentSettingsHandler::UpdateZoomScopeExplanationVisibility() {
+  ChromeZoomLevelPrefs* zoom_level_prefs =
+      Profile::FromWebUI(web_ui())->GetZoomLevelPrefs();
+  base::FundamentalValue per_tab_scope(
+      !(zoom_level_prefs
+            ? zoom_level_prefs->GetZoomScopeIsPerOriginPref()
+            : ChromeZoomLevelPrefs::kZoomScopeSettingDefault));
+
+  web_ui()->CallJavascriptFunctionUnsafe(
+      "ContentSettings.showZoomScopeExplanation", per_tab_scope);
+}
+
 }  // namespace options