Update from https://crrev.com/316786

tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp

 // Copyright 2014 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.
 
 // This clang plugin checks various invariants of the Blink garbage
 // collection infrastructure.
 //
 // Errors are described at:
 // http://www.chromium.org/developers/blink-gc-plugin-errors
 
@@ skipping 366 matching lines @@
             it->second.MarkTraced();
         }
       }
 
       QualType base = expr->getBaseType();
       if (!base->isPointerType())
         return true;
       CXXRecordDecl* decl = base->getPointeeType()->getAsCXXRecordDecl();
       if (decl)
         CheckTraceFieldCall(expr->getMemberName().getAsString(), decl, arg);
+      if (expr->getMemberName().getAsString() == kTraceImplName)
+        delegates_to_traceimpl_ = true;
       return true;
     }
 
     if (CXXMemberCallExpr* expr = dyn_cast<CXXMemberCallExpr>(call)) {
       if (CheckTraceFieldCall(expr) || CheckRegisterWeakMembers(expr))
         return true;
 
       if (expr->getMethodDecl()->getNameAsString() == kTraceImplName) {
         delegates_to_traceimpl_ = true;
         return true;
@@ skipping 1535 matching lines @@
 
  private:
   BlinkGCPluginOptions options_;
 };
 
 }  // namespace
 
 static FrontendPluginRegistry::Add<BlinkGCPluginAction> X(
     "blink-gc-plugin",
     "Check Blink GC invariants");