Implement CSSPaintValue and add a layout test.

third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp

Index: third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
diff --git a/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp b/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
index a252f391b7f1ca66a8341c209607ef5971bf9532..bb8527f43798c813c3ecbcb333837990969a316a 100644
--- a/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
+++ b/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
@@ -9,7 +9,9 @@
 #include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/V8ObjectConstructor.h"
 #include "core/css/CSSComputedStyleDeclaration.h"
+#include "core/css/CSSVariableData.h"
 #include "core/css/cssom/FilteredComputedStylePropertyMap.h"
+#include "core/css/cssom/StyleValueFactory.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/layout/LayoutObject.h"
 #include "modules/csspaint/PaintRenderingContext2D.h"
@@ -66,9 +68,11 @@ CSSPaintDefinition::CSSPaintDefinition(
 
 CSSPaintDefinition::~CSSPaintDefinition() {}
 
-PassRefPtr<Image> CSSPaintDefinition::paint(const LayoutObject& layoutObject,
-                                            const IntSize& size,
-                                            float zoom) {
+PassRefPtr<Image> CSSPaintDefinition::paint(
+    const LayoutObject& layoutObject,
+    const IntSize& size,
+    float zoom,
+    const Vector<RefPtr<CSSVariableData>>& variableData) {
   const IntSize specifiedSize = getSpecifiedSize(size, zoom);
 
   ScriptState::Scope scope(m_scriptState.get());
@@ -96,10 +100,26 @@ PassRefPtr<Image> CSSPaintDefinition::paint(const LayoutObject& layoutObject,
       m_nativeInvalidationProperties, m_customInvalidationProperties,
       layoutObject.node());
 
+  // Parse arguments.
+  CSSStyleValueVector paintArguments;
+  if (RuntimeEnabledFeatures::cssPaintAPIArgumentsEnabled()) {
+    if (variableData.size() != m_inputArgumentTypes.size()) {
+      return nullptr;
+    }
+    for (size_t i = 0; i < variableData.size(); ++i) {
+      const CSSValue* parsedValue =
+          variableData[i].get()->parseForSyntax(m_inputArgumentTypes[i]);
+      if (!parsedValue)
+        return nullptr;
+      paintArguments.appendVector(
+          StyleValueFactory::cssValueToStyleValueVector(*parsedValue));
+    }
+  }
   v8::Local<v8::Value> argv[] = {
       ToV8(renderingContext, m_scriptState->context()->Global(), isolate),
       ToV8(paintSize, m_scriptState->context()->Global(), isolate),
-      ToV8(styleMap, m_scriptState->context()->Global(), isolate)};
+      ToV8(styleMap, m_scriptState->context()->Global(), isolate),
+      ToV8(paintArguments, m_scriptState->context()->Global(), isolate)};
 
   v8::Local<v8::Function> paint = m_paint.newLocal(isolate);
 
@@ -107,7 +127,7 @@ PassRefPtr<Image> CSSPaintDefinition::paint(const LayoutObject& layoutObject,
   block.SetVerbose(true);
 
   V8ScriptRunner::callFunction(paint, m_scriptState->getExecutionContext(),
-                               instance, 3, argv, isolate);
+                               instance, 4, argv, isolate);
 
   // The paint function may have produced an error, in which case produce an
   // invalid image.