CSS: Ignore the CSS cascade in show()/hide()/etc.

Fixes gh-1767
Fixes gh-2071
Closes gh-2180

(cherry picked from commit 86419b10bf)

Conflicts:
	src/css.js
	src/css/defaultDisplay.js
	src/effects.js
	test/data/testsuite.css
	test/unit/css.js
	test/unit/effects.js

src/css/defaultDisplay.js

@@ -1,70 +0,0 @@
-define([
-	"../core",
-	"../manipulation" // appendTo
-], function( jQuery ) {
-
-var iframe,
-	elemdisplay = {
-
-		// Support: Firefox
-		// We have to pre-define these values for FF (#10227)
-		HTML: "block",
-		BODY: "block"
-	};
-
-/**
- * Retrieve the actual display of a element
- * @param {String} name nodeName of the element
- * @param {Object} doc Document object
- */
-// Called only from within defaultDisplay
-function actualDisplay( name, doc ) {
-	var elem = jQuery( doc.createElement( name ) ).appendTo( doc.body ),
-
-		display = jQuery.css( elem[ 0 ], "display" );
-
-	// We don't have any data stored on the element,
-	// so use "detach" method as fast way to get rid of the element
-	elem.detach();
-
-	return display;
-}
-
-/**
- * Try to determine the default display value of an element
- * @param {String} nodeName
- */
-function defaultDisplay( nodeName ) {
-	var doc = document,
-		display = elemdisplay[ nodeName ];
-
-	if ( !display ) {
-		display = actualDisplay( nodeName, doc );
-
-		// If the simple way fails, read from inside an iframe
-		if ( display === "none" || !display ) {
-
-			// Use the already-created iframe if possible
-			iframe = (iframe || jQuery( "<iframe frameborder='0' width='0' height='0'/>" ))
-				.appendTo( doc.documentElement );
-
-			// Always write a new HTML skeleton so Webkit and Firefox don't choke on reuse
-			doc = iframe[ 0 ].contentDocument;
-
-			// Support: IE
-			doc.write();
-			doc.close();
-
-			display = actualDisplay( nodeName, doc );
-			iframe.detach();
-		}
-
-		// Store the correct default display
-		elemdisplay[ nodeName ] = display;
-	}
-
-	return display;
-}
-
-return defaultDisplay;
-});

src/css/showHide.js

@@ -0,0 +1,45 @@
+define([], function() {
+
+function showHide( elements, show ) {
+	var display, elem,
+		values = [],
+		index = 0,
+		length = elements.length;
+
+	// Determine new display value for elements that need to change
+	for ( ; index < length; index++ ) {
+		elem = elements[ index ];
+		if ( !elem.style ) {
+			continue;
+		}
+
+		display = elem.style.display;
+		if ( show ) {
+			if ( display === "none" ) {
+				// Restore a pre-hide() value if we have one
+				values[ index ] = jQuery._data( elem, "display" ) || "";
+			}
+		} else {
+			if ( display !== "none" ) {
+				values[ index ] = "none";
+
+				// Remember the value we're replacing
+				jQuery._data( elem, "display", display );
+			}
+		}
+	}
+
+	// Set the display of the elements in a second loop
+	// to avoid the constant reflow
+	for ( index = 0; index < length; index++ ) {
+		if ( values[ index ] != null ) {
+			elements[ index ].style.display = values[ index ];
+		}
+	}
+
+	return elements;
+}
+
+return showHide;
+
+});