Mark plugin requires restart code/resources Linux-only.

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 1965435ee09ee03014a397c5d2f9507928ca8a94..b304bf895c3464382f4065237b394ac3ccc227e8 100644
--- a/chrome/app/chromium_strings.grd
+++ b/chrome/app/chromium_strings.grd
@@ -1183,9 +1183,11 @@ Please check your email at <ph name="ACCOUNT_EMAIL">$2<ex>jane.doe@example.com</
       </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>
+      <if expr="is_linux">
+        <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>
+      </if>
 
       <!-- Desktop to iOS promotion -->
       <message name="IDS_PASSWORD_MANAGER_DESKTOP_TO_IOS_PROMO_TEXT" desc="Text for Chrome iOS Promotion appearing in the password bubble after a password is saved.">