Core:CSS: Attach test nodes to documentElement, not body

Attaching test divs to document.documentElement instead of document.body
used to cause issues in jQuery 1.x; jQuery Compat doesn't execute any tests
on document ready, though so it could be aligned with master.

This makes jQuery Compat support tests work correctly even if jQuery is
included & used in head before body even exists - making it similar to
the master behavior.

Fixes gh-2502

src/core/ready.js

@@ -38,11 +38,6 @@ jQuery.extend({
 			return;
 		}
 
-		// Make sure body exists, at least, in case IE gets a little overzealous (ticket #5443).
-		if ( !document.body ) {
-			return setTimeout( jQuery.ready );
-		}
-
 		// Remember that the DOM is ready
 		jQuery.isReady = true;
 

src/css/addGetHookIf.js

@@ -4,24 +4,14 @@ function addGetHookIf( conditionFn, hookFn ) {
 	// Define the hook, we'll check on the first run if it's really needed.
 	return {
 		get: function() {
-			var condition = conditionFn();
-
-			if ( condition == null ) {
-				// The test was not ready at this point; screw the hook this time
-				// but check again when needed next time.
-				return;
-			}
-
-			if ( condition ) {
-				// Hook not needed (or it's not possible to use it due to missing dependency),
-				// remove it.
-				// Since there are no other hooks for marginRight, remove the whole object.
+			if ( conditionFn() ) {
+				// Hook not needed (or it's not possible to use it due
+				// to missing dependency), remove it.
 				delete this.get;
 				return;
 			}
 
 			// Hook needed; redefine it so that the support test is not executed again.
-
 			return (this.get = hookFn).apply( this, arguments );
 		}
 	};

src/css/support.js

@@ -88,15 +88,10 @@ define([
 
 	function computeStyleTests() {
 		var contents, divStyle,
-			body = document.body;
-
-		if ( !body || !body.style ) {
-			// Test fired too early or in an unsupported environment, exit.
-			return;
-		}
+			documentElement = document.documentElement;
 
 		// Setup
-		body.appendChild( container );
+		documentElement.appendChild( container );
 
 		div.style.cssText =
 			// Support: Android 2.3
@@ -162,7 +157,7 @@ define([
 		}
 
 		// Teardown
-		body.removeChild( container );
+		documentElement.removeChild( container );
 	}
 
 })();