[Infobars] Initialize InfoBarDelegate::infobar_

InfoBarDelegate::infobar_ was uninitialized during construction - which
is bad for delegates that try to access InfoBarDelegate::infobar().
Properly initialize it to nullptr.

Bug: None
Change-Id: I8f52e02fbca1486f7c60c8f2791cd7e8c464d5d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2387118
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803355}

components/infobars/core/infobar_delegate.cc

@@ -122,7 +122,6 @@ InfoBarDelegate::AsOfflinePageInfoBarDelegate() {
 }
 #endif
 
-InfoBarDelegate::InfoBarDelegate() : nav_entry_id_(0) {
-}
+InfoBarDelegate::InfoBarDelegate() = default;
 
 }  // namespace infobars

components/infobars/core/infobar_delegate.h

@@ -280,10 +280,10 @@ class InfoBarDelegate {
 
  private:
   // The InfoBar associated with us.
-  InfoBar* infobar_;
+  InfoBar* infobar_ = nullptr;
 
   // The ID of the active navigation entry at the time we became owned.
-  int nav_entry_id_;
+  int nav_entry_id_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(InfoBarDelegate);
 };