Update the CrxInstaller and UnpackedInstaller to use the ExtensionInstallChecker

chrome/browser/extensions/extension_install_checker.cc

Index: chrome/browser/extensions/extension_install_checker.cc
diff --git a/chrome/browser/extensions/extension_install_checker.cc b/chrome/browser/extensions/extension_install_checker.cc
index 5aab44d791dbd41ee0fdea06fc7994e40a6599ad..bd02b7100ade59c1cdeb7ee0622f426953d575e9 100644
--- a/chrome/browser/extensions/extension_install_checker.cc
+++ b/chrome/browser/extensions/extension_install_checker.cc
@@ -163,8 +163,12 @@ void ExtensionInstallChecker::MaybeInvokeCallback() {
     running_checks_ = 0;
     ++current_sequence_number_;
 
-    callback_.Run(failed_mask);
+    Callback callback_copy = callback_;
     callback_.Reset();
+
+    // This instance may be owned by the callback recipient and deleted here,
+    // so reset |callback_| first and invoke a copy of the callback.
+    callback_copy.Run(failed_mask);
   }
 }