Generates predicates to test in diff functions in ComputedStyle

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

Index: third_party/WebKit/Source/core/css/ComputedStyleDiffFunctions.json5
diff --git a/third_party/WebKit/Source/core/css/ComputedStyleDiffFunctions.json5 b/third_party/WebKit/Source/core/css/ComputedStyleDiffFunctions.json5
index 0c84d05f0b9dd5f64b16de7bf6cdcb81b736a00e..a4cbb53c8b8d89565ac5875951bdf27952385deb 100644
--- a/third_party/WebKit/Source/core/css/ComputedStyleDiffFunctions.json5
+++ b/third_party/WebKit/Source/core/css/ComputedStyleDiffFunctions.json5
@@ -16,6 +16,15 @@
     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.
+    // The fields are predicate - the predicate to be tested and field_dependencies
+    // which lists the properties this predicate test depends on.

[alancutter (OOO until 2018), 2017/05/24 07:29:36]

List the config fields with bullet points or a skeleton example to make it
easier to find quickly.
Mention the availability of the "other" variable.

[nainar, 2017/05/24 08:01:45]

Done.

+    predicates_to_test: {
+      default: [],
+    },
   },
   data: [
     {
@@ -45,6 +54,16 @@
             method: "BorderRightWidth()",
             field_dependencies: ["border-right-width"]
           }
+        ],
+        predicates_to_test: [
+          {
+            predicate: "TextShadowDataEquivalent(other)",

[nainar, 2017/05/22 03:45:29]

could add the other as an argument bit in field.tmpl but then will have to pass
this in without brackets. so :/

[shend, 2017/05/22 03:51:05]

I would prefer not writing "other" in here, but it may not be possible if
predicates can take arguments.

[nainar1, 2017/05/22 03:52:55]

Yeah - I think leaving it here for the MVP and then seeing what way to go once
we have moved everything over is the best call to make at this stage.  

+            field_dependencies: ["text-shadow"]
+          },
+          {
+            predicate: "QuotesDataEquivalent(other)",
+            field_dependencies: ["quotes"]
+          },
         ]
     },
     {