Don't attempt to unload the same extension twice if multiple ExtensionHost instances existed for th…

chrome/browser/extensions/extension_service.cc

Index: chrome/browser/extensions/extension_service.cc
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index db32e5a39c86f6bd2326edeb6d1e80bef818cc13..da17f664bbc18a77662e4e064ab66e7b95eaaddf 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -2356,6 +2356,7 @@ const Extension* ExtensionService::GetPendingExtensionUpdate(
 void ExtensionService::TrackTerminatedExtension(const Extension* extension) {
   // No need to check for duplicates; inserting a duplicate is a no-op.
   registry_->AddTerminated(make_scoped_refptr(extension));
+  extensions_being_terminated_.erase(extension->id());
   UnloadExtension(extension->id(), UnloadedExtensionInfo::REASON_TERMINATE);
 }
 
@@ -2536,6 +2537,11 @@ void ExtensionService::Observe(int type,
       extensions::ExtensionHost* host =
           content::Details<extensions::ExtensionHost>(details).ptr();
 
+      // If the extension is already being terminated, there is nothing left to
+      // do.
+      if (!extensions_being_terminated_.insert(host->extension_id()).second)
+        break;
+
       // Mark the extension as terminated and Unload it. We want it to
       // be in a consistent state: either fully working or not loaded
       // at all, but never half-crashed.  We do it in a PostTask so