style: Add a Show Password button to <input type=password> controls

It's controlled by the pref:
layout.forms.input-type-show-password-button.enabled

Differential Revision: https://phabricator.services.mozilla.com/D130407

components/style/element_state.rs

@@ -125,6 +125,11 @@ bitflags! {
         const IN_DEVTOOLS_HIGHLIGHTED_STATE = 1 << 45;
         /// Used for the devtools style editor. Probably should go away.
         const IN_STYLEEDITOR_TRANSITIONING_STATE = 1 << 46;
+        /// For :-moz-value-empty (to show widgets like the reveal password
+        /// button or the clear button).
+        const IN_VALUE_EMPTY_STATE = 1 << 47;
+        /// For :-moz-revealed.
+        const IN_REVEALED_STATE = 1 << 48;
     }
 }
 

components/style/gecko/non_ts_pseudo_class_list.rs

@@ -63,6 +63,8 @@ macro_rules! apply_non_ts_list {
                 ("-moz-dir-attr-like-auto", MozDirAttrLikeAuto, IN_HAS_DIR_ATTR_LIKE_AUTO_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
 
                 ("-moz-autofill-preview", MozAutofillPreview, IN_AUTOFILL_PREVIEW_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS_AND_CHROME),
+                ("-moz-value-empty", MozValueEmpty, IN_VALUE_EMPTY_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
+                ("-moz-revealed", MozRevealed, IN_REVEALED_STATE, PSEUDO_CLASS_ENABLED_IN_UA_SHEETS),
 
                 ("-moz-math-increment-script-level", MozMathIncrementScriptLevel, IN_INCREMENT_SCRIPT_LEVEL_STATE, _),
 

components/style/gecko/wrapper.rs

@@ -1975,6 +1975,8 @@ impl<'le> ::selectors::Element for GeckoElement<'le> {
             NonTSPseudoClass::Active |
             NonTSPseudoClass::Hover |
             NonTSPseudoClass::MozAutofillPreview |
+            NonTSPseudoClass::MozRevealed |
+            NonTSPseudoClass::MozValueEmpty |
             NonTSPseudoClass::Dir(..) => self.state().intersects(pseudo_class.state_flag()),
             NonTSPseudoClass::AnyLink => self.is_link(),
             NonTSPseudoClass::Link => {