Oilpan: eagerly finalize WebGLRenderingContext objects.

Source/core/html/canvas/WebGLSharedObject.cpp

Index: Source/core/html/canvas/WebGLSharedObject.cpp
diff --git a/Source/core/html/canvas/WebGLSharedObject.cpp b/Source/core/html/canvas/WebGLSharedObject.cpp
index 0a8cd15f3837a0f1be59bdfc70fa4d7f5a2edce8..e9bf52bd27e6e1d3fcfec998ff3cf49a90a37b2d 100644
--- a/Source/core/html/canvas/WebGLSharedObject.cpp
+++ b/Source/core/html/canvas/WebGLSharedObject.cpp
@@ -56,7 +56,13 @@ void WebGLSharedObject::detachContextGroup()
 
 WebGraphicsContext3D* WebGLSharedObject::getAWebGraphicsContext3D() const
 {
-    return m_contextGroup ? m_contextGroup->getAWebGraphicsContext3D() : nullptr;
+    if (!m_contextGroup)
+        return nullptr;
+
+#if ENABLE(OILPAN) && defined(ADDRESS_SANITIZER)
+    WebGLContextGroup::UnpoisonScope scope(m_contextGroup);
+#endif
+    return m_contextGroup->getAWebGraphicsContext3D();
 }
 
 } // namespace blink