Split Camera and Mic into two permissions on the Site Details page (under Site Settings).

chrome/android/java/res/xml/single_website_preferences.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 The Chromium Authors. All rights reserved.
      Use of this source code is governed by a BSD-style license that can be
      found in the LICENSE file. -->
 
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
     <PreferenceCategory
         android:key="site_heading"
         android:title="@string/website_settings_site_category" />
     <org.chromium.chrome.browser.preferences.TextMessagePreference
         android:key="site_title" />
     <PreferenceCategory
         android:key="site_usage"
         android:title="@string/website_settings_usage_category" />
     <org.chromium.chrome.browser.preferences.website.ClearWebsiteStorage
         android:key="clear_data"
         android:title="@string/webstorage_clear_data_dialog_title"
         android:dialogMessage="@string/webstorage_clear_data_dialog_message"
         android:positiveButtonText="@string/webstorage_clear_data_dialog_ok_button"
         android:negativeButtonText="@string/cancel"
         android:widgetLayout="@layout/clear_storage" />
     <PreferenceCategory
         android:key="site_permissions"
         android:title="@string/website_settings_permissions_category" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="cookies_permission_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
-        android:key="voice_and_video_capture_permission_list" />
+        android:key="video_capture_permission_list" />

[newt (away), 2015/04/22 17:35:54]

"camera_permission_list", similarly below

[Finnur, 2015/04/24 13:51:59]

Done.

+    <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
+        android:key="voice_capture_permission_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="popup_permission_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="images_permission_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="javascript_permission_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="location_access_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="push_notifications_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="midi_sysex_permission_list" />
     <org.chromium.chrome.browser.preferences.ChromeBaseListPreference
         android:key="protected_media_identifier_permission_list" />
     <org.chromium.chrome.browser.preferences.ButtonPreference
         android:key="reset_site_button"
         android:title="@string/website_reset" />
 </PreferenceScreen>