Suppress reflows before RefreshTick or FirstLoad

This fixes a bug where partially loaded content is displayed to the user
before it should be, usually before stylesheets have loaded. This commit
supresses reflows until either FirstLoad or RefreshTick, whichever comes
first.

Unfortunately, hit_test and mouse_over did not do reflows if they were
necessary, and so by suppressing the initial spurious reflows, these
methods started to panic without a display list to query. This patch
also transforms these into queries similar to the other existing
queries.

1 files changed, 20 insertions, 1 deletions

diff --git a/components/layout/layout_thread.rs b/components/layout/layout_thread.rs
index bf4a6ac9745..866c7ac2239 100644
--- a/components/layout/layout_thread.rs
+++ b/components/layout/layout_thread.rs
@@ -22,7 +22,7 @@ use euclid::size::Size2D;
 use flow::{self, Flow, ImmutableFlowUtils, MutableFlowUtils, MutableOwnedFlowUtils};
 use flow_ref::{self, FlowRef};
 use fnv::FnvHasher;
-use gfx::display_list::{ClippingRegion, DisplayList, LayerInfo};
+use gfx::display_list::{ClippingRegion, DisplayItemMetadata, DisplayList, LayerInfo};
 use gfx::display_list::{OpaqueNode, StackingContext, StackingContextId, StackingContextType};
 use gfx::font;
 use gfx::font_cache_thread::FontCacheThread;
@@ -114,6 +114,9 @@ pub struct LayoutThreadData {
     /// A queued response for the client {top, left, width, height} of a node in pixels.
     pub client_rect_response: Rect<i32>,
 
+    /// A queued response for the node at a given point
+    pub hit_test_response: (Option<DisplayItemMetadata>, bool),
+
     /// A queued response for the resolved style property of an element.
     pub resolved_style_response: Option<String>,
 
@@ -458,6 +461,7 @@ impl LayoutThread {
                     content_box_response: Rect::zero(),
                     content_boxes_response: Vec::new(),
                     client_rect_response: Rect::zero(),
+                    hit_test_response: (None, false),
                     resolved_style_response: None,
                     offset_parent_response: OffsetParentResponse::empty(),
                     margin_style_response: MarginStyleResponse::empty(),
@@ -978,6 +982,9 @@ impl LayoutThread {
                     ReflowQueryType::ContentBoxesQuery(_) => {
                         rw_data.content_boxes_response = Vec::new();
                     },
+                    ReflowQueryType::HitTestQuery(_, _) => {
+                        rw_data.hit_test_response = (None, false);
+                    },
                     ReflowQueryType::NodeGeometryQuery(_) => {
                         rw_data.client_rect_response = Rect::zero();
                     },
@@ -1120,6 +1127,18 @@ impl LayoutThread {
                     let node = unsafe { ServoLayoutNode::new(&node) };
                     rw_data.content_boxes_response = process_content_boxes_request(node, &mut root_flow);
                 },
+                ReflowQueryType::HitTestQuery(point, update_cursor) => {
+                    let point = Point2D::new(Au::from_f32_px(point.x), Au::from_f32_px(point.y));
+                    let result = match rw_data.display_list {
+                        None => panic!("Tried to hit test with no display list"),
+                        Some(ref dl) => dl.hit_test(point),
+                    };
+                    rw_data.hit_test_response = if result.len() > 0 {
+                        (Some(result[0]), update_cursor)
+                    } else {
+                        (None, update_cursor)
+                    };
+                },
                 ReflowQueryType::NodeGeometryQuery(node) => {
                     let node = unsafe { ServoLayoutNode::new(&node) };
                     rw_data.client_rect_response = process_node_geometry_request(node, &mut root_flow);