[MD settings] prevent paper-buttons from shrinking

chrome/browser/resources/settings/settings_shared_css.html

 <link rel="import" href="chrome://resources/cr_elements/shared_style_css.html">
 <link rel="import" href="settings_vars_css.html">
 
 <!-- Common styles for Material Design settings. -->
 <dom-module id="settings-shared">
   <template>
     <style include="cr-shared-style">
       :host-context([dir=rtl]) button[is='paper-icon-button-light'] {
         transform: scaleX(-1);  /* Flip on the X axis (aka mirror). */
       }
@@ skipping 18 matching lines @@
       iron-icon {
         flex-shrink: 0;  /* Prevent distortion of icons in cramped UI. */
       }
 
       iron-icon[icon='cr:check'],
       iron-icon[icon='settings:done'] {
        --iron-icon-fill-color: var(--google-green-500);
       }
 
       paper-button {
+        flex-shrink: 0;
         height: 36px;
         margin: 0;
       }
 
       paper-button[toggles][active] {
         background-color: var(--paper-grey-300);
       }
 
       paper-toggle-button {
         @apply(--settings-actionable);
@@ skipping 343 matching lines @@
         transform: rotate(-135deg);
       }
 
       .column-header {
         color: var(--paper-grey-600);
         font-weight: 500;
       }
     </style>
   </template>
 </dom-module>