[wrapper-tracing] Fix WebGL extension and attachment handling

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h

Index: third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h
index b2fd1fb435bd5f30058dd032823f5755ac72a269..b604fb2c75493d58b03ff8cc846d1a5755934fd5 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.h
@@ -792,7 +792,8 @@ class MODULES_EXPORT WebGLRenderingContextBase : public CanvasRenderingContext,
     DraftExtension = 0x01,
   };
 
-  class ExtensionTracker : public GarbageCollected<ExtensionTracker> {
+  class ExtensionTracker : public GarbageCollected<ExtensionTracker>,
+                           public TraceWrapperBase {
    public:
     ExtensionTracker(ExtensionFlags flags, const char* const* prefixes)
         : m_draft(flags & DraftExtension), m_prefixes(prefixes) {}
@@ -858,17 +859,23 @@ class MODULES_EXPORT WebGLRenderingContextBase : public CanvasRenderingContext,
       ExtensionTracker::trace(visitor);
     }
 
+    DEFINE_INLINE_VIRTUAL_TRACE_WRAPPERS() {
+      visitor->traceWrappers(m_extension);
+    }
+
    private:
     TypedExtensionTracker(Member<T>& extensionField,
                           ExtensionFlags flags,
                           const char* const* prefixes)
-        : ExtensionTracker(flags, prefixes), m_extensionField(extensionField) {}
+        : ExtensionTracker(flags, prefixes),
+          m_extensionField(extensionField),
+          m_extension(this, nullptr) {}
 
     GC_PLUGIN_IGNORE("http://crbug.com/519953")
     Member<T>& m_extensionField;
     // ExtensionTracker holds it's own reference to the extension to ensure
     // that it is not deleted before this object's destructor is called
-    Member<T> m_extension;
+    TraceWrapperMember<T> m_extension;
   };
 
   bool m_extensionEnabled[WebGLExtensionNameCount];