use getBoundingClientRect for measuring text size

needed because on chrome 17+ line heights can be fractional

lib/ace/layer/text.js

@@ -103,7 +103,7 @@ var Text = function(parentEl) {
         lineHeight : 1
     };
 
-    this.$measureSizes = function() {
+    this.$measureSizes = useragent.isIE || useragent.isOldGecko ? function() {
         var n = 1000;
         if (!this.$measureNode) {
             var measureNode = this.$measureNode = dom.createElement("div");
@@ -130,7 +130,6 @@ var Text = function(parentEl) {
                     container = container.parentNode;
                 container.appendChild(measureNode);
             }
-
         }
         
         // Size and width can be null if the editor is not visible or
@@ -150,7 +149,42 @@ var Text = function(parentEl) {
 
         // Size and width can be null if the editor is not visible or
         // detached from the document
-        if (size.width == 0 && size.height == 0)
+        if (size.width == 0 || size.height == 0)
+            return null;
+
+        return size;
+    } 
+    : function() {
+        if (!this.$measureNode) {
+            var measureNode = this.$measureNode = dom.createElement("div");
+            var style = measureNode.style;
+
+            style.width = style.height = "auto";
+            style.left = style.top = -100 + "px";
+
+            style.visibility = "hidden";
+            style.position = "fixed";
+            style.overflow = "visible";
+            style.whiteSpace = "nowrap";
+
+            measureNode.innerHTML = "X";
+
+            var container = this.element.parentNode;
+            while (!dom.hasCssClass(container, "ace_editor"))
+                container = container.parentNode;
+            container.appendChild(measureNode);
+        }
+        
+        var rect = this.$measureNode.getBoundingClientRect();
+
+        var size = {
+            height: rect.height,
+            width: rect.width
+        };
+
+        // Size and width can be null if the editor is not visible or
+        // detached from the document
+        if (size.width == 0 || size.height == 0)
             return null;
 
         return size;

lib/ace/scrollbar.js

@@ -83,6 +83,8 @@ var ScrollBar = function(parent) {
         this.inner.style.height = height + "px";
     };
 
+    // TODO: on chrome 17+ after for small zoom levels after this function
+    // this.element.scrollTop != scrollTop which makes page to scroll up.
     this.setScrollTop = function(scrollTop) {
         this.element.scrollTop = scrollTop;
     };