Show a different banner in chrome://settings for extension-controlled settings.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 6b7d835deb11a61cd7653c02d57193f11d16553f..608bd5e2ee7ad30dad40bf0d3dcd1b5c2e6614a2 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -7818,18 +7818,36 @@ ls' lab.">
       </if>
 
       <if expr="pp_ifdef('chromeos')">
-        <message name="IDS_OPTIONS_MANAGED_PREFS" desc="ChromeOS banner displayed in case there are managed options the user won't be able to change.">
-          Some settings have been disabled by your IT administrator.
+        <message name="IDS_OPTIONS_POLICY_MANAGED_PREFS" desc="Banner displayed in case there are policy-managed options the user won't be able to change.">
+          Some settings have been disabled by your administrator.
+        </message>
+        <message name="IDS_OPTIONS_EXTENSION_MANAGED_PREFS" desc="Banner displayed in case there are extension-managed options the user won't be able to change.">
+          Some settings are being managed by an extension.
+        </message>
+        <message name="IDS_OPTIONS_POLICY_EXTENSION_MANAGED_PREFS" desc="Banner displayed in case there are policy- and extension-managed options the user won't be able to change.">
+          Some settings have been disabled by your administrator and others are being managed by an extension.
         </message>
       </if>
       <if expr="not pp_ifdef('chromeos') and is_posix">
-        <message name="IDS_OPTIONS_MANAGED_PREFS" desc="Mac/Linux banner displayed in case there are managed options the user won't be able to change.">
-          Some preferences have been disabled by your IT administrator.
+        <message name="IDS_OPTIONS_POLICY_MANAGED_PREFS" desc="Banner displayed in case there are policy-managed options the user won't be able to change.">
+          Some preferences have been disabled by your administrator.
+        </message>
+        <message name="IDS_OPTIONS_EXTENSION_MANAGED_PREFS" desc="Banner displayed in case there are extension-managed options the user won't be able to change.">
+          Some preferences are being managed by an extension.
+        </message>
+        <message name="IDS_OPTIONS_POLICY_EXTENSION_MANAGED_PREFS" desc="Banner displayed in case there are policy- and extension-managed options the user won't be able to change.">
+          Some preferences have been disabled by your administrator and others are being managed by an extension.
         </message>
       </if>
       <if expr="is_win">
-        <message name="IDS_OPTIONS_MANAGED_PREFS" desc="Windows banner displayed in case there are managed options the user won't be able to change.">
-          Some options have been disabled by your IT administrator.
+        <message name="IDS_OPTIONS_POLICY_MANAGED_PREFS" desc="Banner displayed in case there are policy-managed options the user won't be able to change.">
+          Some options have been disabled by your administrator.
+        </message>
+        <message name="IDS_OPTIONS_EXTENSION_MANAGED_PREFS" desc="Banner displayed in case there are extension-managed options the user won't be able to change.">
+          Some options are being managed by an extension.
+        </message>
+        <message name="IDS_OPTIONS_POLICY_EXTENSION_MANAGED_PREFS" desc="Banner displayed in case there are policy- and extension-managed options the user won't be able to change.">
+          Some options have been disabled by your administrator and others are being managed by an extension.
         </message>
       </if>