Auto merge of #10109 - mbrubeck:compute_damage_short_circuit, r=pcwalton

Fixes for compute_damage

A few changes:

* Make `compute_damage` short-circuit more, by skipping comparisons if they will only set flags that are already set.

* Update some obsolete comments.

* Add a bunch of missing properties to `compute_damage`.

* Set `RECONSTRUCT_FLOW` when `text-decoration` changes, because it can affect text fragment splitting/merging.

I believe this is all of the computed properties except for the animation properties. (I wasn't sure what to do with those.)  After this lands I'd like to work on moving this information into `properties.mako.rs` so that this function can be auto-generated, and so that newly-added properties can default to setting all flags instead of none.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/10109)
<!-- Reviewable:end -->

components/layout/incremental.rs

@@ -145,6 +145,9 @@ macro_rules! add_if_not_equal(
      [ $($effect:ident),* ], [ $($style_struct_getter:ident.$name:ident),* ]) => ({
         if $( ($old.$style_struct_getter().$name != $new.$style_struct_getter().$name) )||* {
             $damage.insert($($effect)|*);
+            true
+        } else {
+            false
         }
     })
 );
@@ -157,46 +160,19 @@ pub fn compute_damage(old: Option<&Arc<ComputedValues>>, new: &ComputedValues) -
 
     let mut damage = RestyleDamage::empty();
 
-    // This checks every CSS property, as enumerated in
-    // impl<'self> CssComputedStyle<'self>
-    // in src/support/netsurfcss/rust-netsurfcss/netsurfcss.rc.
+    // This should check every CSS property, as enumerated in the fields of
+    // http://doc.servo.org/style/properties/struct.ComputedValues.html
 
-    // FIXME: We can short-circuit more of this.
-
-    add_if_not_equal!(old, new, damage,
-                      [ REPAINT ], [
-        get_color.color, get_background.background_color,
-        get_border.border_top_color, get_border.border_right_color,
-        get_border.border_bottom_color, get_border.border_left_color,
-        get_effects.transform, get_box.z_index
-    ]);
-
-    add_if_not_equal!(old, new, damage,
-                      [ REPAINT, STORE_OVERFLOW, REFLOW_OUT_OF_FLOW ], [
-        get_positionoffsets.top, get_positionoffsets.left,
-        get_positionoffsets.right, get_positionoffsets.bottom
-    ]);
-
-    add_if_not_equal!(old, new, damage,
-                      [ REPAINT, STORE_OVERFLOW, BUBBLE_ISIZES, REFLOW_OUT_OF_FLOW, REFLOW ], [
-        get_border.border_top_width, get_border.border_right_width,
-        get_border.border_bottom_width, get_border.border_left_width,
-        get_margin.margin_top, get_margin.margin_right,
-        get_margin.margin_bottom, get_margin.margin_left,
-        get_padding.padding_top, get_padding.padding_right,
-        get_padding.padding_bottom, get_padding.padding_left,
-        get_box.width, get_box.height,
-        get_inheritedtext.text_align, get_text.text_decoration, get_inheritedbox.line_height
-    ]);
+    // FIXME: Test somehow that every property is included.
 
     add_if_not_equal!(old, new, damage,
                       [
-                        REPAINT,
-                        STORE_OVERFLOW,
-                        BUBBLE_ISIZES,
-                        REFLOW_OUT_OF_FLOW,
-                        REFLOW,
-                        RECONSTRUCT_FLOW
+                          REPAINT,
+                          STORE_OVERFLOW,
+                          BUBBLE_ISIZES,
+                          REFLOW_OUT_OF_FLOW,
+                          REFLOW,
+                          RECONSTRUCT_FLOW
                       ], [
         get_box.float, get_box.display, get_box.position, get_box.content,
         get_counters.counter_reset, get_counters.counter_increment,
@@ -206,8 +182,58 @@ pub fn compute_damage(old: Option<&Arc<ComputedValues>>, new: &ComputedValues) -
         // text shaping is re-run.
         get_inheritedtext.letter_spacing, get_inheritedtext.text_rendering,
         get_inheritedtext.text_transform, get_inheritedtext.word_spacing,
+        get_inheritedtext.overflow_wrap, get_inheritedtext.text_justify,
+        get_inheritedtext.white_space, get_inheritedtext.word_break, get_inheritedtext.text_overflow,
         get_font.font_family, get_font.font_style, get_font.font_variant, get_font.font_weight,
-        get_font.font_size, get_font.font_stretch
+        get_font.font_size, get_font.font_stretch,
+        get_inheritedbox.direction, get_inheritedbox.writing_mode,
+        get_inheritedbox.text_orientation,
+        get_text.text_decoration, get_text.unicode_bidi,
+        get_inheritedtable.empty_cells, get_inheritedtable.caption_side,
+        get_column.column_width, get_column.column_count
+    ]) || add_if_not_equal!(old, new, damage,
+                            [ REPAINT, STORE_OVERFLOW, BUBBLE_ISIZES, REFLOW_OUT_OF_FLOW, REFLOW ],
+        [get_border.border_top_width, get_border.border_right_width,
+        get_border.border_bottom_width, get_border.border_left_width,
+        get_margin.margin_top, get_margin.margin_right,
+        get_margin.margin_bottom, get_margin.margin_left,
+        get_padding.padding_top, get_padding.padding_right,
+        get_padding.padding_bottom, get_padding.padding_left,
+        get_box.width, get_box.height,
+        get_inheritedbox.line_height,
+        get_inheritedtext.text_align, get_inheritedtext.text_indent,
+        get_table.table_layout,
+        get_inheritedtable.border_collapse,
+        get_inheritedtable.border_spacing,
+        get_column.column_gap,
+        get_flex.flex_direction
+    ]) || add_if_not_equal!(old, new, damage,
+                            [ REPAINT, STORE_OVERFLOW, REFLOW_OUT_OF_FLOW ], [
+        get_positionoffsets.top, get_positionoffsets.left,
+        get_positionoffsets.right, get_positionoffsets.bottom
+    ]) || add_if_not_equal!(old, new, damage,
+                            [ REPAINT ], [
+        get_color.color, get_background.background_color,
+        get_background.background_image, get_background.background_position,
+        get_background.background_repeat, get_background.background_attachment,
+        get_background.background_clip, get_background.background_origin,
+        get_background.background_size,
+        get_border.border_top_color, get_border.border_right_color,
+        get_border.border_bottom_color, get_border.border_left_color,
+        get_border.border_top_style, get_border.border_right_style,
+        get_border.border_bottom_style, get_border.border_left_style,
+        get_border.border_top_left_radius, get_border.border_top_right_radius,
+        get_border.border_bottom_left_radius, get_border.border_bottom_right_radius,
+        get_box.z_index, get_box._servo_overflow_clip_box,
+        get_inheritedtext._servo_text_decorations_in_effect,
+        get_pointing.cursor, get_pointing.pointer_events,
+        get_effects.box_shadow, get_effects.clip, get_effects.text_shadow, get_effects.filter,
+        get_effects.transform, get_effects.backface_visibility, get_effects.transform_style,
+        get_effects.transform_origin, get_effects.perspective, get_effects.perspective_origin,
+        get_effects.mix_blend_mode, get_effects.image_rendering,
+
+        // Note: May require REFLOW et al. if `visibility: collapse` is implemented.
+        get_inheritedbox.visibility
     ]);
 
     // If the layer requirements of this flow have changed due to the value
@@ -216,7 +242,6 @@ pub fn compute_damage(old: Option<&Arc<ComputedValues>>, new: &ComputedValues) -
         damage.insert(RestyleDamage::rebuild_and_reflow());
     }
 
-    // FIXME: test somehow that we checked every CSS property
     damage
 }