Bug 1559276 - Part 2: Retire the support for 3-valued syntax for posi…

…tion. r=emilio

According to this resolved spec issue:
w3c/csswg-drafts#2140,
we retire the 3-valued <position> on
1. `object-position`
2. `perspective-origin`,
3. `mask-position`
4. `circle()` and `ellipse()`
, but still keep the support for `background-position`.

Besides, I simply run this python script to generate the .ini file:
```
s = sys.argv[1] + ".ini"
with open(s, "w") as f:
    f.write('[{}]\n'.format(sys.argv[1]))
    f.write('  expected: FAIL\n')
    f.write('  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276\n')
```

Differential Revision: https://phabricator.services.mozilla.com/D37126

layout/style/test/property_database.js

@@ -236,12 +236,8 @@ var validGradientAndElementValues = [
   "repeating-radial-gradient(50px 60px at 15% 20%, red, blue)",
   "repeating-radial-gradient(7em 8em at 45px, red, blue)",
 
-  // FIXME(emilio): We should not be allowing 3-value positions anywhere else
-  // than on `background-position`, see
-  // https://github.com/w3c/csswg-drafts/issues/2140.
-  //
   // When that happens this should be moved to the `invalid` list.
-  "repeating-radial-gradient(circle closest-side at left bottom 7in, hsl(2,2%,5%), rgb(1,6,0))",
+  "repeating-radial-gradient(circle closest-side at left 0px bottom 7in, hsl(2,2%,5%), rgb(1,6,0))",
 
   "-moz-image-rect(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==), 2, 10, 10, 2)",
   "-moz-image-rect(url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==), 10%, 50%, 30%, 0%)",
@@ -706,7 +702,7 @@ var basicShapeOtherValues = [
 
   "circle()",
   "circle(at center)",
-  "circle(at top left 20px)",
+  "circle(at top 0px left 20px)",
   "circle(at bottom right)",
   "circle(20%)",
   "circle(300px)",
@@ -722,7 +718,7 @@ var basicShapeOtherValues = [
 
   "ellipse()",
   "ellipse(at center)",
-  "ellipse(at top left 20px)",
+  "ellipse(at top 0px left 20px)",
   "ellipse(at bottom right)",
   "ellipse(20% 20%)",
   "ellipse(300px 50%)",
@@ -792,6 +788,7 @@ var basicShapeInvalidValues = [
   "circle(20% 20%)",
   "circle(at farthest-side)",
   "circle(calc(20px + rubbish))",
+  "circle(at top left 20px)",
 
   "ellipse(at)",
   "ellipse(at 20% 20% 30%)",
@@ -804,6 +801,7 @@ var basicShapeInvalidValues = [
   "ellipse(20%)",
   "ellipse(at farthest-side farthest-side)",
   "ellipse(at top left calc(20px + rubbish))",
+  "ellipse(at top left 20px)",
 
   "polygon(at)",
   "polygon(at 20% 20% 30%)",
@@ -3036,7 +3034,6 @@ var gCSSProperties = {
     type: CSS_TYPE_SHORTHAND_AND_LONGHAND,
     initial_values: [
       "top 0% left 0%",
-      "top 0% left",
       "top left",
       "left top",
       "0% 0%",
@@ -3096,8 +3093,6 @@ var gCSSProperties = {
       "top 3em right 10px",
       "left 15px",
       "10px top",
-      "left top 15px",
-      "left 10px top",
       "left 20%",
       "right 20%",
     ],
@@ -3117,6 +3112,8 @@ var gCSSProperties = {
       "top 20px bottom 20px",
       "left left",
       "0px calc(0px + rubbish)",
+      "left top 15px",
+      "left 10px top",
     ],
   },
   "mask-position-x": {
@@ -3983,7 +3980,7 @@ var gCSSProperties = {
       "top left / 100px auto",
       "top left / 100px 10%",
       "top left / 100px calc(20px)",
-      "bottom right scroll none transparent repeat",
+      "bottom right 8px scroll none transparent repeat",
       "50% transparent",
       "transparent 50%",
       "50%",
@@ -6625,8 +6622,6 @@ var gCSSProperties = {
       "top 3em right 10px",
       "left 15px",
       "10px top",
-      "left top 15px",
-      "left 10px top",
       "left 20%",
       "right 20%",
     ],
@@ -6645,6 +6640,8 @@ var gCSSProperties = {
       "top 20px bottom 20px",
       "left left",
       "20 20",
+      "left top 15px",
+      "left 10px top",
     ],
   },
   opacity: {

servo/components/style/properties/shorthands/background.mako.rs

@@ -15,7 +15,7 @@
     use crate::properties::longhands::background_clip;
     use crate::properties::longhands::background_clip::single_value::computed_value::T as Clip;
     use crate::properties::longhands::background_origin::single_value::computed_value::T as Origin;
-    use crate::values::specified::{Color, Position, PositionComponent};
+    use crate::values::specified::{AllowQuirks, Color, Position, PositionComponent};
     use crate::parser::Parse;
 
     // FIXME(emilio): Should be the same type!
@@ -64,7 +64,9 @@
                     }
                 }
                 if position.is_none() {
-                    if let Ok(value) = input.try(|input| Position::parse(context, input)) {
+                    if let Ok(value) = input.try(|input| {
+                        Position::parse_three_value_quirky(context, input, AllowQuirks::No)
+                    }) {
                         position = Some(value);
 
                         // Parse background size, if applicable.
@@ -211,7 +213,7 @@
         let mut any = false;
 
         input.parse_comma_separated(|input| {
-            let value = Position::parse_quirky(context, input, AllowQuirks::Yes)?;
+            let value = Position::parse_three_value_quirky(context, input, AllowQuirks::Yes)?;
             position_x.push(value.horizontal);
             position_y.push(value.vertical);
             any = true;

servo/components/style/values/specified/position.rs

@@ -94,13 +94,17 @@ impl Parse for Position {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
-        Self::parse_quirky(context, input, AllowQuirks::No)
+        let position = Self::parse_three_value_quirky(context, input, AllowQuirks::No)?;
+        if position.is_three_value_syntax() {
+            return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+        }
+        Ok(position)
     }
 }
 
 impl Position {
-    /// Parses a `<position>`, with quirks.
-    pub fn parse_quirky<'i, 't>(
+    /// Parses a `<bg-position>`, with quirks.
+    pub fn parse_three_value_quirky<'i, 't>(
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
         allow_quirks: AllowQuirks,
@@ -183,6 +187,12 @@ impl Position {
     pub fn center() -> Self {
         Self::new(PositionComponent::Center, PositionComponent::Center)
     }
+
+    /// Returns true if this uses a 3 value syntax.
+    #[inline]
+    fn is_three_value_syntax(&self) -> bool {
+        self.horizontal.component_count() != self.vertical.component_count()
+    }
 }
 
 impl ToCss for Position {
@@ -252,6 +262,17 @@ impl<S> PositionComponent<S> {
     pub fn zero() -> Self {
         PositionComponent::Length(LengthPercentage::Percentage(Percentage::zero()))
     }
+
+    /// Returns the count of this component.
+    fn component_count(&self) -> usize {
+        match *self {
+            PositionComponent::Length(..) |
+            PositionComponent::Center => 1,
+            PositionComponent::Side(_, ref lp) => {
+                if lp.is_some() { 2 } else { 1 }
+            }
+        }
+    }
 }
 
 impl<S: Side> ToComputedValue for PositionComponent<S> {

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-001e.html.ini

@@ -1,3 +1,3 @@
 [object-fit-contain-png-001e.html]
-  fuzzy:
-    if os == "android": maxDifference=26;totalPixels=0-23
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-001i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-001i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-001o.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-001o.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-001p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-001p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-002e.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-002e.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-002i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-002i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-002o.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-002o.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-png-002p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-png-002p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-001i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-001i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-001p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-001p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-002i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-002i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-002p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-002p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-003i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-003i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-003p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-003p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-004i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-004i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-004p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-004p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-005i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-005i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-005p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-005p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-006i.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-006i.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-contain-svg-006p.html.ini

@@ -0,0 +1,3 @@
+[object-fit-contain-svg-006p.html]
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276

testing/web-platform/meta/css/vendor-imports/mozilla/mozilla-central-reftests/images3/object-fit-cover-png-001c.html.ini

@@ -1,7 +1,3 @@
 [object-fit-cover-png-001c.html]
-  expected:
-    if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-    if not debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-    if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-    if not debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-    FAIL
+  expected: FAIL
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1559276