Update: fastPath for fill

Author: kurkle

docs/general/performance.md

@@ -89,7 +89,7 @@ new Chart(ctx, {
 
 ### Automatic data decimation during draw
 
-Line element will automatically decimate data, when the following conditions are met: `tension` is `0`, `steppedLine` is `false` (default), `fill` is `false` and `borderDash` is `[]` (default).`
+Line element will automatically decimate data, when the following conditions are met: `tension` is `0`, `steppedLine` is `false` (default) and `borderDash` is `[]` (default).`
 This improves rendering speed by skipping drawing of invisible line segments.
 
 ```javascript
@@ -109,6 +109,26 @@ new Chart(ctx, {
 });
 ```
 
+### Enable spanGaps
+
+If you have a lot of data points, it can be more performant to enable spanGaps. This disables segmentation of line, which can be an unneeded step.
+
+To enable spanGaps:
+
+```javascript
+new Chart(ctx, {
+    type: 'line',
+    data: {
+        datasets: [{
+            spanGaps: true // enable for a single dataset
+        }]
+    },
+    options: {
+        spanGaps: true // enable for all datasets
+    }
+});
+```
+
 ### Disable Line Drawing
 
 If you have a lot of data points, it can be more performant to disable rendering of the line for a dataset and only draw points. Doing this means that there is less to draw on the canvas which will improve render performance.