Generates predicates to test in diff functions in ComputedStyle

third_party/WebKit/Source/core/css/ComputedStyleDiffFunctions.json5

 {
   // This file specifies the fields we want to diff in the various diff functions 
   // in ComputedStyle.
 
   parameters: {
     // The name parameter represents the name of the function to be created.
 
     fields_to_diff: {
       default: [],
     },
 
     // A list of methods to diff (these can be public getters of fields or 
     // functions that use fields to determine a value).
-    // Each entry is expressed as a dict of two fields.
-    // The fields are method - the method to be diffed and field_dependencies
-    // which lists the properties this method depends on.
+    // Each entry is expressed as a dict of two fields:
+    // 1. method: the method to be diffed
+    // 2. field_dependencies: lists the properties this method depends on.
     methods_to_diff: {
       default: [],
     },
+
+    // A list of predicates that have the diff logic built into them and are only
+    // called by the diff functions in ComputedStyle.
+    // Each entry is expressed as a dict of two fields:
+    // 1. predicate: the predicate to be tested
+    // 2. field_dependencies: lists the properties this predicate test depends on.
+    // TODO: Note that you also have to pass in the arguments for the predicate. 
+    // This may be removed in the future if we are always passing the other ComputedStyle
+    predicates_to_test: {
+      default: [],
+    },
   },
   data: [
     {
         name: "ScrollAnchorDisablingPropertyChanged",
         fields_to_diff: ["width", "min-width", "max-width", "height", "min-height", "max-height", "margin-top", "margin-left", "margin-right", "margin-bottom", 
                   "left", "right", "top", "bottom", "padding-top", 
                   "padding-left", "padding-right", "padding-bottom"],
         methods_to_diff: [
           {
             method: "GetPosition()",
@@ skipping 74 matching lines @@
             method: "GetUnicodeBidi()",
             field_dependencies: ["unicode-bidi"]
           },
           {
             method: "Floating()",
             field_dependencies: ["float"]
           },
           {
             method: "OriginalDisplay()",
             field_dependencies: ["OriginalDisplay"]
+          }
+        ],
+        predicates_to_test: [
+          {
+            predicate: "TextShadowDataEquivalent(other)",
+            field_dependencies: ["text-shadow"]
+          },
+          {
+            predicate: "QuotesDataEquivalent(other)",
+            field_dependencies: ["quotes"]
           },
         ]
     },
     {
         name: "DiffNeedsFullLayout",
         fields_to_diff: ["width", "min-width", "max-width", "height", "min-height", "max-height", "box-sizing"]
     },
     {
         name: "DiffNeedsPaintInvalidationObject",
         methods_to_diff: [
@@ skipping 15 matching lines @@
         name: "DiffNeedsVisualRectUpdate",
         methods_to_diff: [
           {
             method: "Visibility()",
             field_dependencies: ["visibility"]
           }
         ]
     }
   ],
 }