Implement PaintWorkletGlobalScope#registerPaint() for the CSS Paint API

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

Index: third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
diff --git a/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp b/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
index 3509486acdcc5c825fc6d711b6085462ab25477a..03503342e5afa6bc554bc70e952b9c018eca54cb 100644
--- a/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
+++ b/third_party/WebKit/Source/modules/csspaint/PaintWorkletGlobalScope.cpp
@@ -4,8 +4,12 @@
 
 #include "modules/csspaint/PaintWorkletGlobalScope.h"
 
+#include "bindings/core/v8/ScopedPersistent.h"
+#include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/WorkerOrWorkletScriptController.h"
+#include "core/dom/ExceptionCode.h"
 #include "core/inspector/MainThreadDebugger.h"
+#include "modules/csspaint/CSSPaintDefinition.h"
 
 namespace blink {
 
@@ -27,4 +31,91 @@ PaintWorkletGlobalScope::~PaintWorkletGlobalScope()
 {
 }
 
+void PaintWorkletGlobalScope::dispose()
+{
+    // Explicitly clear the paint defininitions to break a reference cycle
+    // between them and this global scope.
+    m_paintDefinitions.clear();
+
+    WorkletGlobalScope::dispose();
+}
+
+void PaintWorkletGlobalScope::registerPaint(const String& name, const ScriptValue& ctorValue, ExceptionState& exceptionState)
+{
+    if (m_paintDefinitions.contains(name)) {
+        exceptionState.throwDOMException(NotSupportedError, "A class with name:'" + name + "' is already registered.");
+        return;
+    }
+
+    if (name.isEmpty()) {
+        exceptionState.throwTypeError("The empty string is not a valid name.");
+        return;
+    }
+
+    v8::Isolate* isolate = scriptController()->getScriptState()->isolate();
+    v8::Local<v8::Context> context = scriptController()->context();
+
+    ASSERT(ctorValue.v8Value()->IsFunction());
+    v8::Local<v8::Function> constructor = v8::Local<v8::Function>::Cast(ctorValue.v8Value());
+
+    v8::Local<v8::Value> inputPropertiesValue;
+    if (!v8Call(constructor->Get(context, v8String(isolate, "inputProperties")), inputPropertiesValue))
+        return;
+
+    if (!isUndefinedOrNull(inputPropertiesValue)) {
+        toImplArray<Vector<String>>(inputPropertiesValue, 0, isolate, exceptionState);
+
+        if (exceptionState.hadException())
+            return;
+
+        // TODO(ikilpatrick): Hook up invalidation based on these inputProperties.
+    }
+
+    v8::Local<v8::Value> prototypeValue;
+    if (!v8Call(constructor->Get(context, v8String(isolate, "prototype")), prototypeValue))
+        return;
+
+    if (isUndefinedOrNull(prototypeValue)) {
+        exceptionState.throwTypeError("The 'prototype' object on the class does not exist.");
+        return;
+    }
+
+    if (!prototypeValue->IsObject()) {
+        exceptionState.throwTypeError("The 'prototype' property on the class is not an object.");
+        return;
+    }
+
+    v8::Local<v8::Object> prototype = v8::Local<v8::Object>::Cast(prototypeValue);
+
+    v8::Local<v8::Value> paintValue;
+    if (!v8Call(prototype->Get(context, v8String(isolate, "paint")), paintValue))
+        return;
+
+    if (isUndefinedOrNull(paintValue)) {
+        exceptionState.throwTypeError("The 'paint' function on the prototype does not exist.");
+        return;
+    }
+
+    if (!paintValue->IsFunction()) {
+        exceptionState.throwTypeError("The 'paint' property on the prototype is not a function.");
+        return;
+    }
+
+    v8::Local<v8::Function> paint = v8::Local<v8::Function>::Cast(paintValue);
+
+    RawPtr<CSSPaintDefinition> definition = CSSPaintDefinition::create(scriptController()->getScriptState(), constructor, paint);
+    m_paintDefinitions.set(name, definition);
+}
+
+CSSPaintDefinition* PaintWorkletGlobalScope::findDefinition(const String& name)
+{
+    return m_paintDefinitions.get(name);
+}
+
+DEFINE_TRACE(PaintWorkletGlobalScope)
+{
+    visitor->trace(m_paintDefinitions);
+    WorkletGlobalScope::trace(visitor);
+}
+
 } // namespace blink