Add setting to isolate zoom changes by default.

chrome/app/settings_strings.grdp

Index: chrome/app/settings_strings.grdp
diff --git a/chrome/app/settings_strings.grdp b/chrome/app/settings_strings.grdp
index b15c8acae6b83725da0f6d9f4c6ea388143c358a..47d530d5c67b93c5963c0a0e11f009c50c2dd580 100644
--- a/chrome/app/settings_strings.grdp
+++ b/chrome/app/settings_strings.grdp
@@ -1795,6 +1795,12 @@
   <message name="IDS_SETTINGS_SITE_SETTINGS_ZOOM_LEVELS" desc="Label for the Zoom levels category in site settings.">
     Zoom levels
   </message>
+  <message name="IDS_SETTINGS_SITE_SETTINGS_ZOOM_SCOPE_ORIGIN" desc="Label of the toggle to enable/disable having the user's zoom changes apply to all tabs that navigate to the origin that was zoomed. This is shown when the toggle is enabled.">
+    When you change a page's zoom, remember the change for all tabs on the same site (recommended)
+  </message>
+  <message name="IDS_SETTINGS_SITE_SETTINGS_ZOOM_SCOPE_TAB" desc="Label of the toggle to enable/disable having the user's zoom changes apply to all tabs that navigate to the origin that was zoomed. This is shown when the toggle is disabled. When it is disabled, zoom changes only apply to the one tab.">
+    When you change a page's zoom, do not zoom other tabs
+  </message>
   <message name="IDS_SETTINGS_SITE_SETTINGS_MAY_SAVE_COOKIES" desc="Label for the cookies option description site settings.">
     Sites can save and read cookie data
   </message>