Remove get_location_with_offset

Now that rust-cssparser reports 1-based locations, bump the required
cssparser version and remove get_location_with_offset.  Previously,
some code paths were not calling get_location_with_offset; see
https://bugzilla.mozilla.org/show_bug.cgi?id=1398869 for some
background.

tests/unit/gfx/Cargo.toml

@@ -10,7 +10,7 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-cssparser = "0.20.2"
+cssparser = "0.21.0"
 gfx = {path = "../../../components/gfx"}
 ipc-channel = "0.8"
 style = {path = "../../../components/style"}

tests/unit/style/Cargo.toml

@@ -12,7 +12,7 @@ doctest = false
 [dependencies]
 byteorder = "1.0"
 app_units = "0.5"
-cssparser = "0.20.2"
+cssparser = "0.21.0"
 euclid = "0.15"
 html5ever = "0.19"
 parking_lot = "0.4"

tests/unit/style/stylesheets.rs

@@ -320,13 +320,13 @@ fn test_report_error_stylesheet() {
     assert_eq!("Unsupported property declaration: 'invalid: true;', \
                 Custom(PropertyDeclaration(UnknownProperty(\"invalid\")))", error.message);
     assert_eq!(9, error.line);
-    assert_eq!(8, error.column);
+    assert_eq!(9, error.column);
 
     let error = errors.pop().unwrap();
     assert_eq!("Unsupported property declaration: 'display: invalid;', \
                 Custom(PropertyDeclaration(InvalidValue(\"display\", None)))", error.message);
     assert_eq!(8, error.line);
-    assert_eq!(8, error.column);
+    assert_eq!(9, error.column);
 
     // testing for the url
     assert_eq!(url, error.url);

tests/unit/stylo/Cargo.toml

@@ -13,7 +13,7 @@ doctest = false
 
 [dependencies]
 atomic_refcell = "0.1"
-cssparser = "0.20.2"
+cssparser = "0.21.0"
 env_logger = "0.4"
 euclid = "0.15"
 geckoservo = {path = "../../../ports/geckolib"}