Switch to using WebRender hit testing

This trades quite a bit of complicated code in Servo for few more
messages and a significant performance improvement. In particular,
WebRender can search the entire display list at once instead of
ping-ponging down the pipeline tree. This allows us to send mouse
events to the correct pipeline immediately.

1 files changed, 34 insertions, 38 deletions

diff --git a/components/layout/webrender_helpers.rs b/components/layout/webrender_helpers.rs
index fbd5d423ddf..4477294fced 100644
--- a/components/layout/webrender_helpers.rs
+++ b/components/layout/webrender_helpers.rs
@@ -19,23 +19,12 @@ use style::values::generics::effects::Filter as GenericFilter;
 use webrender_api::{self, ClipAndScrollInfo, ComplexClipRegion, DisplayListBuilder};
 use webrender_api::{ExtendMode, LayoutTransform};
 
-fn prim_info(local_rect: Rect<Au>,
-             local_clip: Option<webrender_api::LocalClip>) -> webrender_api::LayoutPrimitiveInfo {
-    match local_clip {
-        Some(local_clip) => {
-            webrender_api::LayoutPrimitiveInfo::with_clip(local_rect.to_rectf(), local_clip)
-        }
-        None => {
-            webrender_api::LayoutPrimitiveInfo::new(local_rect.to_rectf())
-        }
-    }
-}
-
 pub trait WebRenderDisplayListConverter {
     fn convert_to_webrender(&self, pipeline_id: PipelineId) -> DisplayListBuilder;
 }
 
 trait WebRenderDisplayItemConverter {
+    fn prim_info(&self) -> webrender_api::LayoutPrimitiveInfo;
     fn convert_to_webrender(&self,
                             builder: &mut DisplayListBuilder,
                             current_clip_and_scroll_info: &mut ClipAndScrollInfo);
@@ -249,6 +238,20 @@ impl WebRenderDisplayListConverter for DisplayList {
 }
 
 impl WebRenderDisplayItemConverter for DisplayItem {
+    fn prim_info(&self) -> webrender_api::LayoutPrimitiveInfo {
+        let tag = match self.base().metadata.pointing {
+            Some(cursor) => Some((self.base().metadata.node.0 as u64, cursor as u8)),
+            None => None,
+        };
+        webrender_api::LayoutPrimitiveInfo {
+            rect: self.base().bounds.to_rectf(),
+            local_clip: self.base().local_clip,
+            // TODO(gw): Make use of the WR backface visibility functionality.
+            is_backface_visible: true,
+            tag: tag,
+        }
+    }
+
     fn convert_to_webrender(&self,
                             builder: &mut DisplayListBuilder,
                             current_clip_and_scroll_info: &mut ClipAndScrollInfo) {
@@ -261,11 +264,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
 
         match *self {
             DisplayItem::SolidColor(ref item) => {
-                let color = item.color;
-                if color.a > 0.0 {
-                    builder.push_rect(&prim_info(item.base.bounds, Some(item.base.local_clip)),
-                                      color);
-                }
+                builder.push_rect(&self.prim_info(), item.color);
             }
             DisplayItem::Text(ref item) => {
                 let mut origin = item.baseline_origin.clone();
@@ -294,7 +293,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                 }
 
                 if glyphs.len() > 0 {
-                    builder.push_text(&prim_info(item.base.bounds, Some(item.base.local_clip)),
+                    builder.push_text(&self.prim_info(),
                                       &glyphs,
                                       item.text_run.font_key,
                                       item.text_color,
@@ -305,7 +304,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                 if let Some(id) = item.webrender_image.key {
                     if item.stretch_size.width > Au(0) &&
                        item.stretch_size.height > Au(0) {
-                        builder.push_image(&prim_info(item.base.bounds, Some(item.base.local_clip)),
+                        builder.push_image(&self.prim_info(),
                                            item.stretch_size.to_sizef(),
                                            item.tile_spacing.to_sizef(),
                                            item.image_rendering.to_image_rendering(),
@@ -314,7 +313,6 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                 }
             }
             DisplayItem::Border(ref item) => {
-                let rect = item.base.bounds;
                 let widths = item.border_widths.to_border_widths();
 
                 let details = match item.details {
@@ -395,7 +393,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                     }
                 };
 
-                builder.push_border(&prim_info(rect, Some(item.base.local_clip)), widths, details);
+                builder.push_border(&self.prim_info(), widths, details);
             }
             DisplayItem::Gradient(ref item) => {
                 let rect = item.base.bounds;
@@ -410,7 +408,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                                        end_point,
                                                        item.gradient.stops.clone(),
                                                        extend_mode);
-                builder.push_gradient(&prim_info(rect, Some(item.base.local_clip)),
+                builder.push_gradient(&self.prim_info(),
                                       gradient,
                                       rect.size.to_sizef(),
                                       webrender_api::LayoutSize::zero());
@@ -428,14 +426,14 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                                               radius,
                                                               item.gradient.stops.clone(),
                                                               extend_mode);
-                builder.push_radial_gradient(&prim_info(rect, Some(item.base.local_clip)),
+                builder.push_radial_gradient(&self.prim_info(),
                                              gradient,
                                              rect.size.to_sizef(),
                                              webrender_api::LayoutSize::zero());
             }
             DisplayItem::Line(ref item) => {
                 let box_bounds = item.base.bounds.to_rectf();
-                builder.push_line(&prim_info(item.base.bounds, Some(item.base.local_clip)),
+                builder.push_line(&self.prim_info(),
                                   box_bounds.origin.y + box_bounds.size.height,
                                   box_bounds.origin.x,
                                   box_bounds.origin.x + box_bounds.size.width,
@@ -445,9 +443,8 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                   item.style);
             }
             DisplayItem::BoxShadow(ref item) => {
-                let rect = item.base.bounds;
                 let box_bounds = item.box_bounds.to_rectf();
-                builder.push_box_shadow(&prim_info(rect, Some(item.base.local_clip)),
+                builder.push_box_shadow(&self.prim_info(),
                                         box_bounds,
                                         item.offset.to_vectorf(),
                                         item.color,
@@ -457,8 +454,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                         item.clip_mode.to_clip_mode());
             }
             DisplayItem::PushTextShadow(ref item) => {
-                let rect = item.base.bounds;
-                builder.push_shadow(&prim_info(rect, Some(item.base.local_clip)),
+                builder.push_shadow(&self.prim_info(),
                                     webrender_api::Shadow {
                                         blur_radius: item.blur_radius.to_f32_px(),
                                         offset: item.offset.to_vectorf(),
@@ -469,9 +465,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                 builder.pop_all_shadows();
             }
             DisplayItem::Iframe(ref item) => {
-                let rect = item.base.bounds;
-                let pipeline_id = item.iframe.to_webrender();
-                builder.push_iframe(&prim_info(rect, Some(item.base.local_clip)), pipeline_id);
+                builder.push_iframe(&self.prim_info(), item.iframe.to_webrender());
             }
             DisplayItem::PushStackingContext(ref item) => {
                 let stacking_context = &item.stacking_context;
@@ -484,13 +478,15 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                     LayoutTransform::from_untyped(&perspective)
                 });
 
-                builder.push_stacking_context(&prim_info(stacking_context.bounds, None),
-                                              stacking_context.scroll_policy,
-                                              transform,
-                                              stacking_context.transform_style,
-                                              perspective,
-                                              stacking_context.mix_blend_mode,
-                                              stacking_context.filters.to_filter_ops());
+                builder.push_stacking_context(
+                    &webrender_api::LayoutPrimitiveInfo::new(stacking_context.bounds.to_rectf()),
+                    stacking_context.scroll_policy,
+                    transform,
+                    stacking_context.transform_style,
+                    perspective,
+                    stacking_context.mix_blend_mode,
+                    stacking_context.filters.to_filter_ops()
+                );
             }
             DisplayItem::PopStackingContext(_) => builder.pop_stacking_context(),
             DisplayItem::DefineClipScrollNode(ref item) => {