Add types ScrollLocation documentation. Insert continue in layers loop instead of early return.

Author: Sam

webrender/src/frame.rs

@@ -328,28 +328,30 @@ impl Frame {
                 continue;
             }
 
-            let mut delta:Point2D<f32> = match scroll_location {
+            let mut delta = match scroll_location {
                 ScrollLocation::Delta(delta) => delta,
                 ScrollLocation::Start => {
-                    if layer.scrolling.offset.y.round() == 0.0 {
-                        // Nothing to do.
-                        return false;
+                    if layer.scrolling.offset.y.round() <= 0.0 {
+                        // Nothing to do on this layer.
+                        continue;
                     }
 
                     layer.scrolling.offset.y = 0.0;
-                    return true;
+                    scrolled_a_layer = true;
+                    continue;
                 },
                 ScrollLocation::End => {
                     let end_pos = -layer.content_size.height +
-                                                 (layer.local_viewport_rect.size.height);
+                                  layer.local_viewport_rect.size.height;
 
-                    if layer.scrolling.offset.y.round() == end_pos {
-                        // Nothing to do.
-                        return false;
+                    if layer.scrolling.offset.y.round() >= end_pos {
+                        // Nothing to do on this layer.
+                        continue;
                     }
 
                     layer.scrolling.offset.y = end_pos;
-                    return true;
+                    scrolled_a_layer = true;
+                    continue;
                 },
             };
 

webrender_traits/src/types.rs

@@ -445,9 +445,12 @@ pub enum ScrollPolicy {
 
 #[derive(Clone, Copy, Debug, Deserialize, Serialize)]
 pub enum ScrollLocation {
-    Delta(Point2D<f32>), // Scroll by a certain amount.
-    Start, // Scroll to very top of element.
-    End // Scroll to very bottom of element.
+    /// Scroll by a certain amount.
+    Delta(Point2D<f32>), 
+    /// Scroll to very top of element.
+    Start,
+    /// Scroll to very bottom of element. 
+    End 
 }
 
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]