Fix some more compile errors after upstream 777180a32b6107 in blink clang plugin

TBR=hans@chromium.org

Bug: none
Change-Id: I0a2cb7a3e995acd5504a894148aee684d4c8a4f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2028207Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736379}

tools/clang/blink_gc_plugin/RecordInfo.cpp

@@ -183,9 +183,9 @@ void RecordInfo::walkBases() {
       if (!base)
         continue;
 
-      const std::string& name = base->getName();
+      llvm::StringRef name = base->getName();
       if (Config::IsGCBase(name)) {
-        gc_base_names_.push_back(name);
+        gc_base_names_.push_back(std::string(name));
         is_gc_derived_ = true;
       }
     }