Made a generator for .h files for implementations of CSSPropertyAPI.h

third_party/WebKit/Source/core/css/BUILD.gn

Index: third_party/WebKit/Source/core/css/BUILD.gn
diff --git a/third_party/WebKit/Source/core/css/BUILD.gn b/third_party/WebKit/Source/core/css/BUILD.gn
index f1ef952cd58b6981cde4889a5e6e346a31a74998..516b977be4f1fd728c280d4e4c9ec97eb925911c 100644
--- a/third_party/WebKit/Source/core/css/BUILD.gn
+++ b/third_party/WebKit/Source/core/css/BUILD.gn
@@ -346,13 +346,9 @@ blink_core_sources("css") {
     "parser/SizesCalcParser.cpp",
     "properties/CSSPropertyAPI.h",
     "properties/CSSPropertyAPIMargin.cpp",
-    "properties/CSSPropertyAPIMargin.h",
     "properties/CSSPropertyAPIWebkitMargin.cpp",
-    "properties/CSSPropertyAPIWebkitMargin.h",
     "properties/CSSPropertyAPIWebkitPadding.cpp",
-    "properties/CSSPropertyAPIWebkitPadding.h",
     "properties/CSSPropertyAPIWillChange.cpp",
-    "properties/CSSPropertyAPIWillChange.h",
     "properties/CSSPropertyDescriptor.h",
     "resolver/AnimatedStyleBuilder.cpp",
     "resolver/AnimatedStyleBuilder.h",