Allow use of a search page that isn't Special:Search

Bug: T279057
Change-Id: I219a28eed0e199c65bfdb21d601509ab8dc0efe1

src/mobile.startup/search/SearchHeaderView.js

@@ -44,6 +44,7 @@ class SearchHeaderView extends View {
 		return util.template( `<div class="overlay-title search-header-view">
 		<form method="get" action="{{action}}" class="search-box">
 		<input class="search mw-ui-background-icon-search" type="search" name="search" autocomplete="off" placeholder="{{placeholderMsg}}" aria-label="{{placeholderMsg}}" value="{{searchTerm}}">
+		<input type="hidden" name="title" value="{{defaultSearchPage}}">
 		</form>
 </div>` );
 	}

src/mobile.startup/search/SearchOverlay.js

@@ -19,6 +19,7 @@ var
  * @param {Object} params Configuration options
  * @param {string} params.placeholderMsg Search input placeholder text.
  * @param {string} [params.action] of form defaults to the value of wgScript
+ * @param {string} [params.defaultSearchPage] The default search page e.g. Special:Search
  * @param {SearchGateway} [params.gateway]
  * @fires SearchOverlay#search-show
  * @fires SearchOverlay#search-start
@@ -31,7 +32,8 @@ function SearchOverlay( params ) {
 			params.action || mw.config.get( 'wgScript' ),
 			function ( query ) {
 				this.performSearch( query );
-			}.bind( this )
+			}.bind( this ),
+			params.defaultSearchPage || ''
 		),
 		options = util.extend( true, {
 			headerChrome: true,

src/mobile.startup/search/searchHeader.js

@@ -8,14 +8,16 @@ const formHeader = require( '../headers' ).formHeader,
  * @param {string} placeholderMsg
  * @param {string} action
  * @param {Function} onInput
+ * @param {string} defaultSearchPage
  * @return {jQuery.Element}
  */
-function searchHeader( placeholderMsg, action, onInput ) {
+function searchHeader( placeholderMsg, action, onInput, defaultSearchPage ) {
 	return formHeader(
 		new SearchHeaderView( {
 			placeholderMsg,
 			action,
-			onInput
+			onInput,
+			defaultSearchPage
 		} ),
 		[
 			icons.cancel()