Generalise search trigger mechanism

Allow content to trigger it.

Bug: T189316
Change-Id: Ie9a66b001b3ea4f79e465747b80b181df948cd34

includes/skins/MinervaTemplate.php

@@ -287,7 +287,7 @@ class MinervaTemplate extends BaseTemplate {
 			// which is problematic in Opera Mini (see T140490)
 			'searchButton' => Html::rawElement( 'button', [
 				'id' => 'searchIcon',
-				'class' => MinervaUI::iconClass( 'magnifying-glass', 'element' ),
+				'class' => MinervaUI::iconClass( 'magnifying-glass', 'element', 'skin-minerva-search-trigger' ),
 			], wfMessage( 'searchbutton' ) ),
 			'secondaryButtonData' => $data['secondaryButtonData'],
 			'mainmenuhtml' => $this->getMainMenuHtml( $data ),

includes/skins/minerva.mustache

@@ -18,7 +18,7 @@
 					</h1>
 				</div>
 				<div class="search-box">
-					<input class="search" type="search" name="search" id="searchInput"
+					<input class="search skin-minerva-search-trigger" type="search" name="search" id="searchInput"
 					   autocomplete="off" placeholder="{{placeholder}}"
 					   value="{{search}}">
 				</div>

resources/skins.minerva.scripts/search.js

@@ -43,7 +43,7 @@
 	// focus() (see SearchOverlay#show) opens virtual keyboard only if triggered
 	// from user context event, so using it in route callback won't work
 	// http://stackoverflow.com/questions/6837543/show-virtual-keyboard-on-mobile-phones-in-javascript
-	$( '#searchInput, #searchIcon' ).on( 'click', openSearchOverlay )
+	$( '#searchInput, #searchIcon, .skin-minerva-search-trigger' ).on( 'click', openSearchOverlay )
 		// Apparently needed for main menu to work correctly.
 		.prop( 'readonly', true );