FYI: Adds V8PrivateProperty::getOrUndefined().

third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h

Index: third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h b/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
index 8d7269577dce7423779dd0294673b1bdfeca9ddb..a7096f94e9147634f76964cb5227dda2fcace846 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
+++ b/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
@@ -27,7 +27,18 @@ class ScriptWrappable;
     X(IntersectionObserver, Callback) \
     X(MutationObserver, Callback) \
     X(PerformanceObserver, Callback) \
-    X(V8NodeFilterCondition, Filter)
+    X(V8NodeFilterCondition, Filter) \
+    X(WebGLRenderingContext, Extensions) \
+    X(WebGLRenderingContext, Misc) \
+    X(WebGLRenderingContext, Queries) \
+    X(WebGLRenderingContext, Samplers) \
+    X(WebGLRenderingContext, Textures2D) \
+    X(WebGLRenderingContext, Textures2DArray) \
+    X(WebGLRenderingContext, Textures3D) \
+    X(WebGLRenderingContext, TexturesCubeMap) \
+    X(WebGLFramebuffer, Attachments) \
+    X(WebGLProgram, Shaders) \
+    X(WebGLVertexArrayObjectBase, Buffers)
 
 // The getter's name for a private property.
 #define V8_PRIVATE_PROPERTY_GETTER_NAME(InterfaceName, PrivateKeyName) \
@@ -72,6 +83,11 @@ public:
             return v8CallBoolean(object->HasPrivate(context, m_privateSymbol));
         }
 
+        v8::Local<v8::Value> getOrUndefined(v8::Local<v8::Context> context, v8::Local<v8::Object> object) const
+        {
+            return v8CallOrCrash(object->GetPrivate(context, m_privateSymbol));
+        }
+
         v8::Local<v8::Value> get(v8::Local<v8::Context> context, v8::Local<v8::Object> object) const
         {
             if (!v8CallBoolean(object->HasPrivate(context, m_privateSymbol)))