Switch BlinkGCPluginConsumer to use ranged for-loops.

tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.h

Index: tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.h
diff --git a/tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.h b/tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.h
index b1e35ce06955b7010815c8ff81cda5a2bb1308cf..d0b49d89bf2a1dc0b7edfd6b4ef6f2320d32a61c 100644
--- a/tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.h
+++ b/tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.h
@@ -96,13 +96,14 @@ class BlinkGCPluginConsumer : public clang::ASTConsumer {
                                  clang::CXXRecordDecl* base);
   void ReportFieldsRequireTracing(RecordInfo* info,
                                   clang::CXXMethodDecl* trace);
-  void ReportClassContainsInvalidFields(RecordInfo* info,
-                                        CheckFieldsVisitor::Errors* errors);
+  void ReportClassContainsInvalidFields(
+      RecordInfo* info,
+      const CheckFieldsVisitor::Errors& errors);
   void ReportClassContainsGCRoots(RecordInfo* info,
-                                  CheckGCRootsVisitor::Errors* errors);
+                                  const CheckGCRootsVisitor::Errors& errors);
   void ReportFinalizerAccessesFinalizedFields(
       clang::CXXMethodDecl* dtor,
-      CheckFinalizerVisitor::Errors* fields);
+      const CheckFinalizerVisitor::Errors& errors);
   void ReportClassRequiresFinalization(RecordInfo* info);
   void ReportClassDoesNotRequireFinalization(RecordInfo* info);
   void ReportClassMustDeclareGCMixinTraceMethod(RecordInfo* info);