Make sure that pointer to the ExtensionsService is valid in the extensions infobars.

chrome/browser/extensions/crashed_extension_infobar.cc

Index: chrome/browser/extensions/crashed_extension_infobar.cc
diff --git a/chrome/browser/extensions/crashed_extension_infobar.cc b/chrome/browser/extensions/crashed_extension_infobar.cc
index 80ab865fb078dc8f739280a9c4808b1bc1c6d226..219a134666dacd1524b835a98f311af5ed8e9d35 100644
--- a/chrome/browser/extensions/crashed_extension_infobar.cc
+++ b/chrome/browser/extensions/crashed_extension_infobar.cc
@@ -20,10 +20,13 @@ CrashedExtensionInfoBarDelegate::CrashedExtensionInfoBarDelegate(
       extensions_service_(extensions_service),
       extension_id_(extension->id()),
       extension_name_(extension->name()) {
-  DCHECK(extensions_service_);
+  DCHECK(extensions_service_.get());
   DCHECK(!extension_id_.empty());
 }
 
+CrashedExtensionInfoBarDelegate::~CrashedExtensionInfoBarDelegate() {
+}
+
 std::wstring CrashedExtensionInfoBarDelegate::GetMessageText() const {
   return l10n_util::GetStringF(IDS_EXTENSION_CRASHED_INFOBAR_MESSAGE,
       UTF8ToWide(extension_name_));