Implement restart-required message on Linux.

chrome/app/chromium_strings.grd

Index: chrome/app/chromium_strings.grd
diff --git a/chrome/app/chromium_strings.grd b/chrome/app/chromium_strings.grd
index 745d072bdfdb47c8f156e2f43a2c9d0273b17887..ebbda16b08f5b4215f20f856a57fca02116226e1 100644
--- a/chrome/app/chromium_strings.grd
+++ b/chrome/app/chromium_strings.grd
@@ -1208,6 +1208,11 @@ Please check your email at <ph name="ACCOUNT_EMAIL">$2<ex>jane.doe@example.com</
         Chromium Tab
       </message>
 
+      <!-- Plugin Placeholders -->
+      <message name="IDS_PLUGIN_RESTART_REQUIRED" desc="The placeholder text for a plugin that can't be loaded until the browser is restarted.">
+        Restart Chromium to enable <ph name="PLUGIN_NAME">$1<ex>Flash</ex></ph>
+      </message>
+
       <!-- Runtime permission strings -->
       <if expr="is_android">
         <message name="IDS_INFOBAR_MISSING_CAMERA_PERMISSION_TEXT" desc="Text shown in an infobar when a website has requested access to the camera capabilities, but Chrome is missing the Android camera permission.">