Add the Mac OSX Keychain message to the Passwords Page.

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_CHECK_FOR_UPDATES" desc="The button label to check for updates and apply (download and install) if found">
       Check for updates
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_CURRENT_CHANNEL_STABLE" desc="The stable label in the message about current channel.">
       stable
@@ skipping 243 matching lines @@
   </message>
   <message name="IDS_SETTINGS_PASSWORDS_WEBSITE" desc="Label for the website a password is for when editing a password.">
     Website
   </message>
   <message name="IDS_SETTINGS_PASSWORDS_USERNAME" desc="Label for the saved username when editing a password.">
     Username
   </message>
   <message name="IDS_SETTINGS_PASSWORDS_PASSWORD" desc="Label for the saved password when editing a password.">
     Password
   </message>
-  <message name="IDS_SETTINGS_PASSWORDS_MANAGE_PASSWORDS" desc="Shown in the passwords section of settings. Descriptive text to inform that passwords can be accessed online. Has a link.">
-    Access your passwords from any device at <ph name="BEGIN_LINK">&lt;a is="action-link" href="$1" target="_blank"&gt;</ph>passwords.google.com<ph name="END_LINK">&lt;/a&gt;</ph>
-  </message>
+  <if expr="is_macosx">
+    <then>
+      <message name="IDS_SETTINGS_PASSWORDS_MANAGE_PASSWORDS" desc="Shown in the passwords section of settings. Descriptive text to inform that passwords can be accessed online. Has a link. Also notifies mac users that chrome will sync passwords to the OS's Keychain, so their passwords will be synced to other chrome profiles.">
+        Access your passwords from any device at <ph name="BEGIN_LINK">&lt;a is="action-link" href="$1" target="_blank"&gt;</ph>passwords.google.com<ph name="END_LINK">&lt;/a&gt;</ph>. On Mac, passwords may be saved to your Keychain and accessed or synced by other Chrome users sharing this OS X account.
+      </message>
+    </then>
+    <else>
+      <message name="IDS_SETTINGS_PASSWORDS_MANAGE_PASSWORDS" desc="Shown in the passwords section of settings. Descriptive text to inform that passwords can be accessed online. Has a link.">
+        Access your passwords from any device at <ph name="BEGIN_LINK">&lt;a is="action-link" href="$1" target="_blank"&gt;</ph>passwords.google.com<ph name="END_LINK">&lt;/a&gt;</ph>
+      </message>
+    </else>
+  </if>
 
   <!-- Default Browser Page -->
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_DEFAULT_BROWSER" desc="Name of the Default Browser page, which allows users to set which browser will open .html files within the OS.">
       Default browser
     </message>
   </if>
 
   <!-- Bluetooth Page -->
   <if expr="chromeos">
@@ skipping 1100 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>