Auto merge of #10717 - pcwalton:wr-overflow-scroll, r=glennw

layout: Implement support for `overflow: scroll` in WebRender.

Requires a WebRender upgrade.

r? @glennw

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components/layout/display_list_builder.rs

@@ -1294,8 +1294,9 @@ impl FragmentDisplayListBuilding for Fragment {
                                scroll_policy: ScrollPolicy,
                                mode: StackingContextCreationMode)
                                -> Box<StackingContext> {
+        let use_webrender = opts::get().use_webrender;
         let border_box = match mode {
-            StackingContextCreationMode::InnerScrollWrapper => {
+            StackingContextCreationMode::InnerScrollWrapper if !use_webrender => {
                 Rect::new(Point2D::zero(), base_flow.overflow.scroll.size)
             }
             _ => {
@@ -1308,9 +1309,12 @@ impl FragmentDisplayListBuilding for Fragment {
             }
         };
         let overflow = match mode {
-            StackingContextCreationMode::InnerScrollWrapper => {
+            StackingContextCreationMode::InnerScrollWrapper if !use_webrender => {
                 Rect::new(Point2D::zero(), base_flow.overflow.paint.size)
             }
+            StackingContextCreationMode::InnerScrollWrapper if use_webrender => {
+                Rect::new(Point2D::zero(), base_flow.overflow.scroll.size)
+            }
             StackingContextCreationMode::OuterScrollWrapper => {
                 Rect::new(Point2D::zero(), border_box.size)
             }

components/layout/layout_thread.rs

@@ -949,8 +949,8 @@ impl LayoutThread {
                     let pipeline_id = self.id.to_webrender();
 
                     // TODO(gw) For now only create a root scrolling layer!
-                    let root_scroll_layer_id = webrender_traits::ScrollLayerId::new(pipeline_id, 0);
                     let mut frame_builder = WebRenderFrameBuilder::new(pipeline_id);
+                    let root_scroll_layer_id = frame_builder.next_scroll_layer_id();
                     let sc_id = rw_data.display_list.as_ref().unwrap().convert_to_webrender(
                         &mut self.webrender_api.as_mut().unwrap(),
                         pipeline_id,

components/layout/webrender_helpers.rs

@@ -268,11 +268,16 @@ impl WebRenderStackingContextConverter for StackingContext {
             }
 
             if child.context_type == StackingContextType::Real {
+                let scroll_layer_id_for_children = if self.scrolls_overflow_area {
+                    scroll_layer_id
+                } else {
+                    None
+                };
                 let stacking_context_id = child.convert_to_webrender(traversal,
                                                                      api,
                                                                      pipeline_id,
                                                                      epoch,
-                                                                     None,
+                                                                     scroll_layer_id_for_children,
                                                                      scroll_policy,
                                                                      frame_builder);
                 builder.push_stacking_context(stacking_context_id);
@@ -299,7 +304,7 @@ impl WebRenderStackingContextConverter for StackingContext {
                                 api: &mut webrender_traits::RenderApi,
                                 pipeline_id: webrender_traits::PipelineId,
                                 epoch: webrender_traits::Epoch,
-                                scroll_layer_id: Option<webrender_traits::ScrollLayerId>,
+                                mut scroll_layer_id: Option<webrender_traits::ScrollLayerId>,
                                 mut scroll_policy: ScrollPolicy,
                                 frame_builder: &mut WebRenderFrameBuilder)
                                 -> webrender_traits::StackingContextId {
@@ -324,7 +329,13 @@ impl WebRenderStackingContextConverter for StackingContext {
                                                    self.blend_mode.to_blend_mode(),
                                                    self.filters.to_filter_ops(),
                                                    &mut frame_builder.auxiliary_lists_builder);
+
         let mut builder = webrender_traits::DisplayListBuilder::new();
+
+        if self.scrolls_overflow_area {
+            scroll_layer_id = Some(frame_builder.next_scroll_layer_id());
+        }
+
         self.convert_children_to_webrender(traversal,
                                            api,
                                            pipeline_id,
@@ -502,7 +513,8 @@ pub struct WebRenderFrameBuilder {
     pub stacking_contexts: Vec<(StackingContextId, webrender_traits::StackingContext)>,
     pub display_lists: Vec<(DisplayListId, webrender_traits::BuiltDisplayList)>,
     pub auxiliary_lists_builder: AuxiliaryListsBuilder,
-    pub root_pipeline_id: PipelineId
+    pub root_pipeline_id: PipelineId,
+    pub next_scroll_layer_id: usize,
 }
 
 impl WebRenderFrameBuilder {
@@ -512,6 +524,7 @@ impl WebRenderFrameBuilder {
             display_lists: vec![],
             auxiliary_lists_builder: AuxiliaryListsBuilder::new(),
             root_pipeline_id: root_pipeline_id,
+            next_scroll_layer_id: 0,
         }
     }
 
@@ -538,5 +551,12 @@ impl WebRenderFrameBuilder {
         self.display_lists.push((id, display_list));
         id
     }
+
+    pub fn next_scroll_layer_id(&mut self) -> webrender_traits::ScrollLayerId {
+        let scroll_layer_id = self.next_scroll_layer_id;
+        self.next_scroll_layer_id += 1;
+        webrender_traits::ScrollLayerId::new(self.root_pipeline_id, scroll_layer_id)
+    }
+
 }
 

components/servo/Cargo.lock

@@ -2320,7 +2320,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender#46dd3f0ffe2e3a650171fd651b522ed072ccf799"
+source = "git+https://github.com/servo/webrender#8d778dac5398cadd093136bc9cf0afbbb61a2b52"
 dependencies = [
  "app_units 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2343,7 +2343,7 @@ dependencies = [
 [[package]]
 name = "webrender_traits"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender_traits#69125172bcea93fd79be48d846eae63d50ddc8ea"
+source = "git+https://github.com/servo/webrender_traits#d1a3bb53f87891bbba8576d05260caee147dc5d8"
 dependencies = [
  "app_units 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",

ports/cef/Cargo.lock

@@ -2195,7 +2195,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender#46dd3f0ffe2e3a650171fd651b522ed072ccf799"
+source = "git+https://github.com/servo/webrender#8d778dac5398cadd093136bc9cf0afbbb61a2b52"
 dependencies = [
  "app_units 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2218,7 +2218,7 @@ dependencies = [
 [[package]]
 name = "webrender_traits"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender_traits#69125172bcea93fd79be48d846eae63d50ddc8ea"
+source = "git+https://github.com/servo/webrender_traits#d1a3bb53f87891bbba8576d05260caee147dc5d8"
 dependencies = [
  "app_units 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",

ports/gonk/Cargo.lock

@@ -2145,7 +2145,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender#46dd3f0ffe2e3a650171fd651b522ed072ccf799"
+source = "git+https://github.com/servo/webrender#8d778dac5398cadd093136bc9cf0afbbb61a2b52"
 dependencies = [
  "app_units 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2168,7 +2168,7 @@ dependencies = [
 [[package]]
 name = "webrender_traits"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender_traits#69125172bcea93fd79be48d846eae63d50ddc8ea"
+source = "git+https://github.com/servo/webrender_traits#d1a3bb53f87891bbba8576d05260caee147dc5d8"
 dependencies = [
  "app_units 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",