layout: Remove the validate_display_list_geometry debugging tool.

I don't think anyone was using it, and it's incompatible with taking
display lists out of flows.

components/layout/block.rs

@@ -64,7 +64,6 @@ use style::properties::ComputedValues;
 use style::values::computed::{LengthOrNone, LengthOrPercentageOrNone};
 use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto};
 use util::geometry::MAX_RECT;
-use util::opts;
 use util::print_tree::PrintTree;
 
 /// Information specific to floated blocks.
@@ -2122,9 +2121,6 @@ impl Flow for BlockFlow {
     fn build_display_list(&mut self, state: &mut DisplayListBuildState) {
         self.build_display_list_for_block(state, BorderPaintingMode::Separate);
         self.fragment.restyle_damage.remove(REPAINT);
-        if opts::get().validate_display_list_geometry {
-            self.base.validate_display_list_geometry();
-        }
     }
 
     fn repair_style(&mut self, new_style: &Arc<ComputedValues>) {

components/layout/display_list_builder.rs

@@ -1853,10 +1853,6 @@ impl InlineFlowDisplayListBuilding for InlineFlow {
             self.base.build_display_items_for_debugging_tint(state,
                                                              self.fragments.fragments[0].node);
         }
-
-        if opts::get().validate_display_list_geometry {
-            self.base.validate_display_list_geometry();
-        }
     }
 }
 

components/layout/flex.rs

@@ -31,7 +31,6 @@ use style::logical_geometry::LogicalSize;
 use style::properties::ComputedValues;
 use style::properties::style_structs;
 use style::values::computed::LengthOrPercentageOrAuto;
-use util::opts;
 
 // A mode describes which logical axis a flex axis is parallel with.
 // The logical axises are inline and block, the flex axises are main and cross.
@@ -422,10 +421,6 @@ impl Flow for FlexFlow {
 
     fn build_display_list(&mut self, state: &mut DisplayListBuildState) {
         self.build_display_list_for_flex(state);
-
-        if opts::get().validate_display_list_geometry {
-            self.block_flow.base.validate_display_list_geometry();
-        }
     }
 
     fn collect_stacking_contexts(&mut self,

components/layout/flow.rs

@@ -1167,37 +1167,6 @@ impl BaseFlow {
         p as usize
     }
 
-    /// Ensures that all display list items generated by this flow are within the flow's overflow
-    /// rect. This should only be used for debugging.
-    pub fn validate_display_list_geometry(&self) {
-        // FIXME(pcwalton, #2795): Get the real container size.
-        let container_size = Size2D::zero();
-        let position_with_overflow = self.position
-                                         .to_physical(self.writing_mode, container_size)
-                                         .union(&self.overflow.paint);
-        let bounds = Rect::new(self.stacking_relative_position, position_with_overflow.size);
-
-        let items = match self.display_list_building_result {
-            Some(ref items) => items,
-            None => return,
-        };
-
-        for item in items.iter() {
-            let base_item = item.item.base();
-            let mut paint_bounds = base_item.clip.clone();
-            paint_bounds.intersect_rect(&base_item.bounds);
-            if !paint_bounds.might_be_nonempty() {
-                continue;
-            }
-
-            if bounds.union(&paint_bounds.bounding_rect()) != bounds {
-                error!("DisplayList item {:?} outside of Flow overflow ({:?})",
-                       item.item,
-                       paint_bounds);
-            }
-        }
-    }
-
     pub fn flow_id(&self) -> usize {
         return self as *const BaseFlow as usize;
     }

components/layout/list_item.rs

@@ -25,7 +25,6 @@ use style::computed_values::{list_style_type, position};
 use style::logical_geometry::LogicalSize;
 use style::properties::ComputedValues;
 use text;
-use util::opts;
 
 /// A block with the CSS `display` property equal to `list-item`.
 #[derive(Debug)]
@@ -144,9 +143,6 @@ impl Flow for ListItemFlow {
 
     fn build_display_list(&mut self, state: &mut DisplayListBuildState) {
         self.build_display_list_for_list_item(state);
-        if opts::get().validate_display_list_geometry {
-            self.block_flow.base.validate_display_list_geometry();
-        }
     }
 
     fn collect_stacking_contexts(&mut self,

components/util/opts.rs

@@ -163,9 +163,6 @@ pub struct Opts {
     /// Emits notifications when there is a relayout.
     pub relayout_event: bool,
 
-    /// Whether to show an error when display list geometry escapes flow overflow regions.
-    pub validate_display_list_geometry: bool,
-
     /// Whether Style Sharing Cache is used
     pub disable_share_style_cache: bool,
 
@@ -254,9 +251,6 @@ pub struct DebugOptions {
     /// Write layout trace to an external file for debugging.
     pub trace_layout: bool,
 
-    /// Display an error when display list geometry escapes overflow region.
-    pub validate_display_list_geometry: bool,
-
     /// Disable the style sharing cache.
     pub disable_share_style_cache: bool,
 
@@ -308,7 +302,6 @@ impl DebugOptions {
                 "show-parallel-layout" => debug_options.show_parallel_layout = true,
                 "paint-flashing" => debug_options.paint_flashing = true,
                 "trace-layout" => debug_options.trace_layout = true,
-                "validate-display-list-geometry" => debug_options.validate_display_list_geometry = true,
                 "disable-share-style-cache" => debug_options.disable_share_style_cache = true,
                 "convert-mouse-to-touch" => debug_options.convert_mouse_to_touch = true,
                 "replace-surrogates" => debug_options.replace_surrogates = true,
@@ -351,8 +344,6 @@ pub fn print_debug_usage(app: &str) -> ! {
     print_option("show-parallel-layout", "Mark which thread laid each flow out with colors.");
     print_option("paint-flashing", "Overlay repainted areas with a random color.");
     print_option("trace-layout", "Write layout trace to an external file for debugging.");
-    print_option("validate-display-list-geometry",
-                 "Display an error when display list geometry escapes overflow region.");
     print_option("disable-share-style-cache",
                  "Disable the style sharing cache.");
     print_option("parallel-display-list-building", "Build display lists in parallel.");
@@ -486,7 +477,6 @@ pub fn default_opts() -> Opts {
         dump_display_list_optimized: false,
         dump_layer_tree: false,
         relayout_event: false,
-        validate_display_list_geometry: false,
         profile_script_events: false,
         profile_heartbeats: false,
         disable_share_style_cache: false,
@@ -727,7 +717,6 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         dump_display_list_optimized: debug_options.dump_display_list_optimized,
         dump_layer_tree: debug_options.dump_layer_tree,
         relayout_event: debug_options.relayout_event,
-        validate_display_list_geometry: debug_options.validate_display_list_geometry,
         disable_share_style_cache: debug_options.disable_share_style_cache,
         convert_mouse_to_touch: debug_options.convert_mouse_to_touch,
         exit_after_load: opt_match.opt_present("x"),