Helpers: resetActivePageHeight() ignores fixed toolbars

Any external fixed toolbar widget with option updatePagePadding set to true
need not be accounted for when calculating page height, because it updates the
page padding to account for itself.

Closes gh-7802
Fixes gh-7739

js/helpers.js

@@ -10,13 +10,32 @@ define( [ "jquery", "./ns", "jquery-ui/jquery.ui.core" ], function( jQuery ) {
 (function( $, window, undefined ) {
 
 	// Subtract the height of external toolbars from the page height, if the page does not have
-	// internal toolbars of the same type
+	// internal toolbars of the same type. We take care to use the widget options if we find a
+	// widget instance and the element's data-attributes otherwise.
 	var compensateToolbars = function( page, desiredHeight ) {
 		var pageParent = page.parent(),
 			toolbarsAffectingHeight = [],
-			externalHeaders = pageParent.children( ":jqmData(role='header')" ),
+
+			// We use this function to filter fixed toolbars with option updatePagePadding set to
+			// true (which is the default) from our height subtraction, because fixed toolbars with
+			// option updatePagePadding set to true compensate for their presence by adding padding
+			// to the active page. We want to avoid double-counting by also subtracting their
+			// height from the desired page height.
+			noPadders = function() {
+				var theElement = $( this ),
+					widgetOptions = $.mobile.toolbar && theElement.data( "mobile-toolbar" ) ?
+						theElement.toolbar( "option" ) : {
+							position: theElement.attr( "data-" + $.mobile.ns + "position" ),
+							updatePagePadding: ( theElement.attr( "data-" + $.mobile.ns +
+								"update-page-padding" ) !== false )
+						};
+
+				return !( widgetOptions.position === "fixed" &&
+					widgetOptions.updatePagePadding === true );
+			},
+			externalHeaders = pageParent.children( ":jqmData(role='header')" ).filter( noPadders ),
 			internalHeaders = page.children( ":jqmData(role='header')" ),
-			externalFooters = pageParent.children( ":jqmData(role='footer')" ),
+			externalFooters = pageParent.children( ":jqmData(role='footer')" ).filter( noPadders ),
 			internalFooters = page.children( ":jqmData(role='footer')" );
 
 		// If we have no internal headers, but we do have external headers, then their height