Garbage collect extensions only if there are no pending extension installs that could still be usin…

chrome/browser/extensions/pending_extension_manager.cc

Index: chrome/browser/extensions/pending_extension_manager.cc
diff --git a/chrome/browser/extensions/pending_extension_manager.cc b/chrome/browser/extensions/pending_extension_manager.cc
index e0ed9a1dc37c1955d9ed91be432bf2f5ca4b8135..b86b0eb38f3cb2f321568ffcb6ac65b4b7481f9d 100644
--- a/chrome/browser/extensions/pending_extension_manager.cc
+++ b/chrome/browser/extensions/pending_extension_manager.cc
@@ -73,6 +73,10 @@ bool PendingExtensionManager::IsIdPending(const std::string& id) const {
   return false;
 }
 
+bool PendingExtensionManager::HasPendingExtensions() const {
+  return !pending_extension_list_.empty();
+}
+
 bool PendingExtensionManager::HasPendingExtensionFromSync() const {
   PendingExtensionList::const_iterator iter;
   for (iter = pending_extension_list_.begin();