FYI: Adds V8PrivateProperty::getOrUndefined().

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

 // Copyright 2016 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.
 
 #ifndef V8PrivateProperty_h
 #define V8PrivateProperty_h
 
 #include "bindings/core/v8/ScopedPersistent.h"
 #include "bindings/core/v8/ScriptPromiseProperties.h"
 #include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/V8PerIsolateData.h"
 #include "core/CoreExport.h"
 #include "wtf/Allocator.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 #include <v8.h>
 
 namespace blink {
 
 class ScriptState;
 class ScriptWrappable;
 
 // Apply |X| for each pair of (InterfaceName, PrivateKeyName).
 #define V8_PRIVATE_PROPERTY_FOR_EACH(X) \
     X(MessageEvent, CachedData) \
     X(PrivateScriptRunner, IsInitialized) \
     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) \
     get##InterfaceName##PrivateKeyName
 
 // The member variable's name for a private property.
 #define V8_PRIVATE_PROPERTY_MEMBER_NAME(InterfaceName, PrivateKeyName) \
     m_symbol##InterfaceName##PrivateKeyName
 
 // The string used to create a private symbol.  Must be unique per V8 instance.
@@ skipping 24 matching lines @@
     // expensive compared to get or set a private property.  This class
     // provides a way to cache a private symbol and re-use it.
     class CORE_EXPORT Symbol {
         STACK_ALLOCATED();
     public:
         bool hasValue(v8::Local<v8::Context> context, v8::Local<v8::Object> object) const
         {
             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)))
                 return v8::Local<v8::Value>();
             v8::Local<v8::Value> value;
             if (v8Call(object->GetPrivate(context, m_privateSymbol), value))
                 return value;
             return v8::Local<v8::Value>();
         }
 
@@ skipping 51 matching lines @@
 
 #define V8_PRIVATE_PROPERTY_DECLARE_MEMBER(InterfaceName, KeyName) \
     ScopedPersistent<v8::Private> V8_PRIVATE_PROPERTY_MEMBER_NAME(InterfaceName, KeyName); // NOLINT(readability/naming/underscores)
     V8_PRIVATE_PROPERTY_FOR_EACH(V8_PRIVATE_PROPERTY_DECLARE_MEMBER)
 #undef V8_PRIVATE_PROPERTY_DECLARE_MEMBER
 };
 
 } // namespace blink
 
 #endif // V8PrivateProperty_h