Index: src/wp-admin/js/common.js
===================================================================
--- src/wp-admin/js/common.js	(revision 31325)
+++ src/wp-admin/js/common.js	(working copy)
@@ -730,6 +730,127 @@
 				}
 			} );
 
+			var wpTouchMenu = {
+				started: false,
+				tracking: false,
+				startPosition: 0,
+				open: false,
+				rtl: ( 'rtl' == document.documentElement.getAttribute( 'dir' ) )
+			};
+
+			$( window ).on( 'touchstart.wp-responsive', function( e ) {
+				var touches = e.originalEvent.touches,
+				touch,
+				winWidth = Math.max( window.innerWidth, document.documentElement.clientWidth );
+
+				// if it's multi touch bail
+				if ( 1 != touches.length ) {
+					return;
+				}
+
+				touch = touches[0];
+
+				// if the menu is open and we're starting from the
+				// outside it start closing the menu
+				if ( wpTouchMenu.open && ! $( e.target ).closest( '#adminmenu' ).length ) {
+					wpTouchMenu.started = true;
+					wpTouchMenu.startPosition = touch.screenX;
+					return;
+				}
+
+				// if it's within the left 20% of the screen
+				// note that it has started
+				if (
+					( ! wpTouchMenu.rtl && touch.screenX <= ( winWidth * 0.2 ) ) ||
+					( wpTouchMenu.rtl && ( winWidth - ( winWidth * 0.2 ) ) <= touch.screenX )
+				) {
+					wpTouchMenu.started = true;
+					wpTouchMenu.startPosition = touch.screenX;
+				}
+			} );
+
+			$( window ).on( 'touchmove.wp-responsive', function( e ) {
+				var touches, touch;
+				// if it didn't qualify for potential menu
+				// open bail
+				if ( ! wpTouchMenu.started ) {
+					return;
+				}
+
+				touches = e.originalEvent.changedTouches;
+
+				// no multitouch
+				if ( 1 != touches.length ) {
+					return;
+				}
+
+				// stop back action
+				e.preventDefault();
+
+				touch = touches[0];
+
+				// cancel open if we're not going in the right direction
+				if (
+					( ! wpTouchMenu.rtl && ! wpTouchMenu.open && touch.screenX <= wpTouchMenu.startPosition ) ||
+					( ! wpTouchMenu.rtl && wpTouchMenu.open && wpTouchMenu.startPosition <= touch.screenX ) ||
+					( wpTouchMenu.rtl && ! wpTouchMenu.open && wpTouchMenu.startPosition <= touch.screenX ) ||
+					( wpTouchMenu.rtl && wpTouchMenu.open && touch.screenX <= wpTouchMenu.startPosition )
+				) {
+					wpTouchMenu.started = false;
+					wpTouchMenu.startPosition = 0;
+					return;
+				}
+
+				wpTouchMenu.tracking = true;
+			} );
+
+			$( window ).on( 'touchend.wp-responsive', function( e ) {
+				var touches = e.originalEvent.changedTouches,
+				touch,
+				winWidth = Math.max( window.innerWidth, document.documentElement.clientWidth ),
+				moved = 0;
+
+				// only process if we're tracking
+				if ( ! wpTouchMenu.tracking ) {
+					return;
+				}
+
+				// no multitouch
+				if ( 1 != touches.length ) {
+					wpTouchMenu.started = false;
+					wpTouchMenu.startPosition = 0;
+					wpTouchMenu.tracking = false;
+					return;
+				}
+
+				touch = touches[0];
+				// calculate how far we've moved
+				if ( wpTouchMenu.rtl ) {
+					if ( wpTouchMenu.open ) {
+						moved = touch.screenX - wpTouchMenu.startPosition;
+					} else {
+						moved = wpTouchMenu.startPosition - touch.screenX;
+					}
+				} else {
+					if ( wpTouchMenu.open ) {
+						moved = wpTouchMenu.startPosition - touch.screenX;
+					} else {
+						moved = touch.screenX - wpTouchMenu.startPosition;
+					}
+				}
+
+				// if it's 20% or more trigger the menu
+				if ( ( winWidth * 0.2 ) <= moved ) {
+					$( '#wp-admin-bar-menu-toggle' ).trigger( 'click' );
+					wpTouchMenu.open = ! wpTouchMenu.open;
+				}
+
+				// reset our values
+				wpTouchMenu.started = false;
+				wpTouchMenu.startPosition = 0;
+				wpTouchMenu.tracking = false;
+			} );
+
 			// Add menu events
 			$adminmenu.on( 'click.wp-responsive', 'li.wp-has-submenu > a', function( event ) {
 				if ( ! $adminmenu.data('wp-responsive') ) {