Consistently wrap WebAuthn resources in a conditional.

It should be desktop only.

Change-Id: I3e498cbd9fe5a9abfa798c4f3719bf7089aa02f5
Reviewed-on: https://chromium-review.googlesource.com/1174998Reviewed-by: Balazs Engedy <engedy@chromium.org>
Commit-Queue: Balazs Engedy <engedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583032}

chrome/app/generated_resources.grd

@@ -9036,6 +9036,7 @@ Please help our engineers fix this problem. Tell us what happened right before y
     </if>
 
     <!-- Web-modal dialog shown during Web Authenticaton API requests. -->
+    <if expr="is_win or is_macosx or desktop_linux or chromeos">
       <message name="IDS_WEBAUTHN_INITIAL_SHEET_TITLE" desc="Title of the dialog shown when a web site wants to register/verify a user's security key through the Web Authentication API.">
       <ph name="APP_NAME">$1<ex>google.com</ex></ph> wants to verify your identity
       </message>
@@ -9129,6 +9130,7 @@ Please help our engineers fix this problem. Tell us what happened right before y
       <message name="IDS_WEBAUTHN_BLE_ACTIVATE_DESCRIPTION" desc="Contents of the dialog shown when the user tries to sign-in using a security key.">
         To use most keys, simply press the button
      </message>
+   </if>
   </messages>
  </release>
 </grit>