MD Settings: Pointers: Avoid setting mouse swap pref while mouse pressed

chrome/browser/resources/settings/device_page/pointers.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-radio-button/paper-radio-button.html">
 <link rel="import" href="../controls/settings_radio_group.html">
 <link rel="import" href="../controls/settings_slider.html">
 <link rel="import" href="../controls/settings_toggle_button.html">
 <link rel="import" href="device_page_browser_proxy.html">
 <link rel="import" href="../settings_shared_css.html">
 
 <dom-module id="settings-pointers">
   <template>
@@ skipping 11 matching lines @@
 
       .subsection > .list-frame {
         -webkit-margin-start: var(--settings-indent-width);
       }
     </style>
     <div id="mouse" hidden$="[[!hasMouse]]"
         class$="[[getSubsectionClass_(hasMouse, hasTouchpad)]]">
       <!-- Subsection title only appears if both mouse and touchpad exist. -->
       <h2 hidden$="[[!hasTouchpad]]">$i18n{mouseTitle}</h2>
       <div class="settings-box first">
-        <settings-toggle-button class="start"
+        <!-- Do not change the mouse button pref before the mouse is released.
+             See crbug.com/686949 -->
+        <settings-toggle-button id="mouseSwapButton" class="start"
             pref="{{prefs.settings.mouse.primary_right}}"
-            label="$i18n{mouseSwapButtons}">
+            label="$i18n{mouseSwapButtons}"
+            on-settings-boolean-control-change="onMouseSwapButtonsChange_"
+            on-down="onMouseSwapButtonsDown_" on-up="onMouseSwapButtonsUp_"
+            no-set-pref>
         </settings-toggle-button>
       </div>
       <div class="settings-box">
         <div class="start" id="mouseSpeedLabel">$i18n{mouseSpeed}</div>
         <settings-slider pref="{{prefs.settings.mouse.sensitivity2}}"
             tick-values="[[sensitivityValues_]]"
             aria-labelledby="mouseSpeedLabel"
             label-min="$i18n{pointerSlow}"
             label-max="$i18n{pointerFast}">
         </settings-slider>
@@ skipping 36 matching lines @@
                 on-keydown="onLearnMoreLinkActivated_">
               $i18n{naturalScrollLearnMore}
             </a>
           </paper-radio-button>
         </settings-radio-group>
       </div>
     </div>
   </template>
   <script src="pointers.js"></script>
 </dom-module>