[animation-worklet] Implement registerAnimator in worklet scope

third_party/WebKit/Source/modules/compositorworker/AnimatorDefinition.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "modules/compositorworker/AnimatorDefinition.h"
+
+#include "bindings/core/v8/ScriptState.h"
+#include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8ObjectConstructor.h"
+#include "core/dom/ExecutionContext.h"
+#include "modules/compositorworker/Animator.h"
+
+namespace blink {
+
+AnimatorDefinition* AnimatorDefinition::create(
+    ScriptState* scriptState,
+    v8::Local<v8::Function> constructor,
+    v8::Local<v8::Function> animate) {
+  return new AnimatorDefinition(scriptState, constructor, animate);

[flackr, 2017/03/13 19:04:51]

I think error checking the animate function on the prototype would make more
sense to put here where the animate function is used.

+}
+
+AnimatorDefinition::AnimatorDefinition(ScriptState* scriptState,
+                                       v8::Local<v8::Function> constructor,
+                                       v8::Local<v8::Function> animate)
+    : m_scriptState(scriptState),
+      m_constructor(scriptState->isolate(), constructor),
+      m_animate(scriptState->isolate(), animate) {}
+
+AnimatorDefinition::~AnimatorDefinition() {}
+
+Animator* AnimatorDefinition::createInstance() {
+  v8::Isolate* isolate = m_scriptState->isolate();
+  v8::Local<v8::Function> constructor = m_constructor.newLocal(isolate);
+  DCHECK(!isUndefinedOrNull(constructor));
+
+  v8::Local<v8::Object> instance;
+  if (!V8ObjectConstructor::newInstance(isolate, constructor)
+           .ToLocal(&instance)) {
+    instance = v8::Local<v8::Object>();
+  }
+
+  return Animator::create(m_scriptState.get(), this, instance);
+}
+
+void AnimatorDefinition::animate(v8::Local<v8::Object> animatorInstance) {
+  ScriptState::Scope scope(m_scriptState.get());
+
+  v8::Isolate* isolate = m_scriptState->isolate();
+
+  if (isUndefinedOrNull(animatorInstance))
+    return;
+
+  v8::Local<v8::Function> animate = m_animate.newLocal(isolate);
+
+  v8::TryCatch block(isolate);
+  block.SetVerbose(true);
+
+  V8ScriptRunner::callFunction(animate, m_scriptState->getExecutionContext(),
+                               animatorInstance, 0, nullptr, isolate);
+
+  // The animate function may have produced an error!
+  if (block.HasCaught())

[flackr, 2017/03/13 19:04:51]

Should we not be catching this error? Or logging it somewhere?

+    return;
+}
+
+}  // namespace blink