Fixes #1275; Fixes #1277

src/expr/x-styling.html

@@ -131,15 +131,15 @@
         // TODO(sorvell): don't redo parsing work each time as below; 
         // instead create a sheet with just custom properties
         for (var i=0, l=styles.length, s; (i<l) && (s=styles[i]); i++) {
-          cssText += this._transformCss(s.textContent, this.is, b) + '\n\n'; 
+          cssText += this._transformCss(s.textContent, b) + '\n\n'; 
         }
         return cssText.trim();
       },
 
-      _transformCss: function(cssText, scope, callback) {
+      _transformCss: function(cssText, callback) {
         return Polymer.Settings.useNativeShadow ?
           Polymer.StyleUtil.toCssText(cssText, callback) : 
-          Polymer.StyleTransformer.css(cssText, scope, callback);
+          Polymer.StyleTransformer.css(cssText, this.is, this.extends, callback);
       },
 
       _xScopeCount: 0,

src/features/standard/styling.html

@@ -107,9 +107,8 @@
           } else {
             var rules = this._rulesForStyle(s);
             Polymer.StyleUtil.applyCss(
-              Polymer.StyleTransformer.css(rules, this.is), 
-              this.is
-            );
+              Polymer.StyleTransformer.css(rules, this.is, this.extends), 
+              this.is, null, true);
           }
         }
       },

src/lib/style-transformer.html

@@ -64,29 +64,34 @@
     // a string of scoped css where each selector is transformed to include
     // a class created from the scope. ShadowDOM selectors are also transformed
     // (e.g. :host) to use the scoping selector.
-    function transformCss(rules, scope, callback) {
+    function transformCss(rules, scope, ext, callback) {
+      var hostScope = calcHostScope(scope, ext);
       return Polymer.StyleUtil.toCssText(rules, function(rule) {
-        transformRule(rule, scope);
+        transformRule(rule, scope, hostScope);
         if (callback) {
-          callback(rule, scope);
+          callback(rule, scope, hostScope);
         }
       });
     }
 
+    function calcHostScope(scope, ext) {
+      return ext ? '[is=' +  scope + ']' : scope;
+    }
+
     // transforms a css rule to a scoped rule.
-    function transformRule(rule, scope) {
+    function transformRule(rule, scope, hostScope) {
       var p$ = rule.selector.split(COMPLEX_SELECTOR_SEP);
       for (var i=0, l=p$.length, p; (i<l) && (p=p$[i]); i++) {
-        p$[i] = transformComplexSelector(p, scope);
+        p$[i] = transformComplexSelector(p, scope, hostScope);
       }
       rule.selector = p$.join(COMPLEX_SELECTOR_SEP);
     }
 
-    function transformComplexSelector(selector, scope) {
+    function transformComplexSelector(selector, scope, hostScope) {
       var stop = false;
       selector = selector.replace(SIMPLE_SELECTOR_SEP, function(s) {
         if (!stop) {
-          var o = transformCompoundSelector(s, scope);
+          var o = transformCompoundSelector(s, scope, hostScope);
           if (o.stop) {
             stop = true;
           }
@@ -100,17 +105,16 @@
       return selector;
     }
 
-    function transformCompoundSelector(selector, scope) {
+    function transformCompoundSelector(selector, scope, hostScope) {
       // replace :host with host scoping class
       var jumpIndex = selector.search(SCOPE_JUMP);
       if (selector.indexOf(HOST) >=0) {
-        var r = scope;
         // :host(...)
         selector = selector.replace(HOST_PAREN, function(m, host, paren) {
-          return r + paren;
+          return hostScope + paren;
         });
         // now normal :host
-        selector = selector.replace(HOST, r);
+        selector = selector.replace(HOST, hostScope);
       // replace other selectors with scoping class
       } else if (jumpIndex !== 0) {
         selector = transformSimpleSelector(selector, scope);

src/lib/style-util.html

@@ -43,17 +43,18 @@
     }
 
     // add a string of cssText to the document.
-    function applyCss(cssText, moniker, target) {
+    function applyCss(cssText, moniker, target, lowPriority) {
       var style = document.createElement('style');
       if (moniker) {
         style.setAttribute('scope', moniker);
       }
       style.textContent = cssText;
-      // TODO(sorvell): investigate if it's better to batch multiple
-      // styles, perhaps into a fragment that's appended at once? (hopefully
-      // this doesn't matter)
       target = target || document.head;
-      Polymer.dom(target).appendChild(style);
+      if (lowPriority) {
+        target.insertBefore(style, target.firstChild);
+      } else {
+        target.appendChild(style);
+      }
       return style;
     }
 

test/unit/scoped-styling-elements.html

@@ -1,4 +1,4 @@
-<dom-module id="x-child" encapsulate>
+<dom-module id="x-child">
   <template>
     <div id="simple">simple</div>
     <div id="complex1" class="scoped">complex1</div>
@@ -14,7 +14,7 @@
   });
 </script>
 
-<dom-module id="x-styled" encapsulate>
+<dom-module id="x-styled">
   <style>
     :host {
       display: block;
@@ -50,6 +50,10 @@
     x-child /deep/ .deepTarget {
       border: 8px solid red;
     }
+
+    #priority {
+      border: 9px solid orange;
+    }
   </style>
   <template>
     <div id="simple">simple</div>
@@ -60,10 +64,33 @@
       <content></content>
     </div>
     <x-child id="child"></x-child>
+    <div id="priority">priority</div>
   </template>
 </dom-module>
 <script>
   Polymer({
     is: 'x-styled'
   });
+</script>
+
+<dom-module id="x-button">
+  <style>
+    :host {
+      border: 10px solid beige;
+    }
+
+    :host(.special) {
+      border: 11px solid beige;
+    }
+
+  </style>
+  <template>
+    Button!
+  </template>
+</dom-module>
+<script>
+  Polymer({
+    is: 'x-button',
+    extends: 'button'
+  });
 </script>

test/unit/scoped-styling.html

@@ -15,6 +15,11 @@
   <script src="../../../web-component-tester/browser.js"></script>
   <link rel="import" href="../../polymer.html">
   <link rel="import" href="scoped-styling-elements.html">
+  <style>
+    #priority[style-scope=x-styled] {
+      border: 1px solid black;
+    }
+  </style>
 </head>
 <body>
 
@@ -26,12 +31,17 @@
 
   <x-styled class="wide"></x-styled>
 
+  <button is="x-button"></button>
+  <button class="special" is="x-button"></button>
+
 <script>
 
   suite('scoped-styling', function() {
     var styled = document.querySelector('x-styled');
     var styledWide = document.querySelector('x-styled.wide');
     var unscoped = document.querySelector('.scoped');
+    var button = document.querySelector('[is=x-button]');
+    var specialButton = document.querySelector('[is=x-button].special');
 
     function assertComputed(element, value) {
       var computed = getComputedStyle(element);
@@ -84,7 +94,20 @@
       Polymer.dom(styled.root).appendChild(d);
       assertComputed(d, '4px');
       Polymer.dom(styled.root).removeChild(d);
-      assert.equal(d.className, 'scoped');
+      assert.equal(d.getAttribute('style-scoped'), null);
+      Polymer.dom(styled.root).appendChild(d);
+      assertComputed(d, '4px');
+      Polymer.dom(styled.root).removeChild(d);
+      assert.equal(d.getAttribute('style-scoped'), null);
+    });
+
+    test('element style precedence below document styles', function() {
+      assertComputed(styledWide.$.priority, '1px');
+    });
+
+    test('type extension elements', function() {
+      assertComputed(button, '10px');
+      assertComputed(specialButton, '11px');
     });
 
   });