[DONT COMMIT] Worklet: Implement "addModule()" algorithm for main thread worklets

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

Index: third_party/WebKit/Source/modules/csspaint/PaintWorklet.cpp
diff --git a/third_party/WebKit/Source/modules/csspaint/PaintWorklet.cpp b/third_party/WebKit/Source/modules/csspaint/PaintWorklet.cpp
index d4ba23475c976898a79d9812442c75c369609f3a..dd0d9278140fb302e5d2ac57f3e1687ea69cf2dd 100644
--- a/third_party/WebKit/Source/modules/csspaint/PaintWorklet.cpp
+++ b/third_party/WebKit/Source/modules/csspaint/PaintWorklet.cpp
@@ -8,6 +8,7 @@
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/csspaint/PaintWorkletGlobalScope.h"
+#include "modules/csspaint/PaintWorkletGlobalScopeProxy.h"
 
 namespace blink {
 
@@ -16,33 +17,46 @@ PaintWorklet* PaintWorklet::Create(LocalFrame* frame) {
   return new PaintWorklet(frame);
 }
 
-PaintWorklet::PaintWorklet(LocalFrame* frame)
-    : MainThreadWorklet(frame),
-      paint_worklet_global_scope_(PaintWorkletGlobalScope::Create(
-          frame,
-          frame->GetDocument()->Url(),
-          frame->GetDocument()->UserAgent(),
-          frame->GetDocument()->GetSecurityOrigin(),
-          ToIsolate(frame->GetDocument()))) {}
+PaintWorklet::PaintWorklet(LocalFrame* frame) : MainThreadWorklet(frame) {}
 
 PaintWorklet::~PaintWorklet() {}
 
-PaintWorkletGlobalScope* PaintWorklet::GetWorkletGlobalScopeProxy() const {
-  return paint_worklet_global_scope_.Get();
-}
-
 CSSPaintDefinition* PaintWorklet::FindDefinition(const String& name) {
-  return paint_worklet_global_scope_->FindDefinition(name);
+  for (const auto& proxy : global_scope_proxies_) {
+    PaintWorkletGlobalScope* global_scope =
+        PaintWorkletGlobalScopeProxy::From(proxy.get())->global_scope();
+    CSSPaintDefinition* definition = global_scope->FindDefinition(name);
+    if (definition)
+      return definition;
+  }
+  return nullptr;
 }
 
 void PaintWorklet::AddPendingGenerator(const String& name,
                                        CSSPaintImageGeneratorImpl* generator) {
-  return paint_worklet_global_scope_->AddPendingGenerator(name, generator);
+  for (const auto& proxy : global_scope_proxies_) {
+    PaintWorkletGlobalScope* global_scope =
+        PaintWorkletGlobalScopeProxy::From(proxy.get())->global_scope();
+    global_scope->AddPendingGenerator(name, generator);
+  }
 }
 
 DEFINE_TRACE(PaintWorklet) {
-  visitor->Trace(paint_worklet_global_scope_);
   MainThreadWorklet::Trace(visitor);
 }
 
+void PaintWorklet::MayAddWorkletGlobalScopes() {
+  // "The user agent must have, and select from at least two
+  // PaintWorkletGlobalScopes in the worklet's WorkletGlobalScopes list, unless
+  // the user agent is under memory constraints."
+  // https://drafts.css-houdini.org/css-paint-api-1/#drawing-an-image
+  //
+  // TODO(nhiroki): Create at least two global scopes.
+  if (!global_scope_proxies_.IsEmpty())
+    return;
+  std::unique_ptr<WorkletGlobalScopeProxy> proxy =
+      PaintWorkletGlobalScopeProxy::Create(frame_);
+  global_scope_proxies_.insert(std::move(proxy));
+}
+
 }  // namespace blink