Add method for identifying different InfoBars

chrome/browser/ui/hung_plugin_tab_helper.cc

Index: chrome/browser/ui/hung_plugin_tab_helper.cc
diff --git a/chrome/browser/ui/hung_plugin_tab_helper.cc b/chrome/browser/ui/hung_plugin_tab_helper.cc
index 7fe0eb5174a93ddadd86adee778e79d53b11b870..5a9956d0a44cf8fd741e7f64b5c74a17ff5db875 100644
--- a/chrome/browser/ui/hung_plugin_tab_helper.cc
+++ b/chrome/browser/ui/hung_plugin_tab_helper.cc
@@ -146,6 +146,7 @@ class HungPluginInfoBarDelegate : public ConfirmInfoBarDelegate {
   ~HungPluginInfoBarDelegate() override;
 
   // ConfirmInfoBarDelegate:
+  std::string GetIdentifier() const override;
   int GetIconId() const override;
   base::string16 GetMessageText() const override;
   int GetButtons() const override;
@@ -186,6 +187,10 @@ HungPluginInfoBarDelegate::HungPluginInfoBarDelegate(
 HungPluginInfoBarDelegate::~HungPluginInfoBarDelegate() {
 }
 
+std::string HungPluginInfoBarDelegate::GetIdentifier() const {
+  return "HungPluginInfoBarDelegate";
+}
+
 int HungPluginInfoBarDelegate::GetIconId() const {
   return IDR_INFOBAR_PLUGIN_CRASHED;
 }