Implement PaintWorkletGlobalScope#registerPaint() for the CSS Paint API

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

Index: third_party/WebKit/Source/modules/csspaint/WindowPaintWorklet.cpp
diff --git a/third_party/WebKit/Source/modules/csspaint/WindowPaintWorklet.cpp b/third_party/WebKit/Source/modules/csspaint/WindowPaintWorklet.cpp
index 3e1165655c4a636622b66e7c3952f77dc46e42fd..c854bfb2df5e953d7b6281ac2eeb9402ec976d57 100644
--- a/third_party/WebKit/Source/modules/csspaint/WindowPaintWorklet.cpp
+++ b/third_party/WebKit/Source/modules/csspaint/WindowPaintWorklet.cpp
@@ -4,6 +4,7 @@
 
 #include "modules/csspaint/WindowPaintWorklet.h"
 
+#include "bindings/core/v8/WorkerOrWorkletScriptController.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/csspaint/PaintWorklet.h"
@@ -46,6 +47,13 @@ PaintWorklet* WindowPaintWorklet::paintWorklet(ExecutionContext* executionContex
     return m_paintWorklet.get();
 }
 
+void WindowPaintWorklet::willDetachGlobalObjectFromFrame()

[ikilpatrick, 2016/03/30 19:12:50]

I'm not sure if the dispose call on the scriptController should be in this or
willDestroyGlobalObjectInFrame.

I believe it should be this as the window's perContextData gets disposed of
here:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

This is called from document->detach as few lines above.

Thoughts?

+{
+    if (m_paintWorklet)
+        m_paintWorklet->workletGlobalScope()->scriptController()->dispose();
+    DOMWindowProperty::willDetachGlobalObjectFromFrame();
+}
+
 DEFINE_TRACE(WindowPaintWorklet)
 {
     visitor->trace(m_paintWorklet);