Add a non-blocking "OneShotEvent" class

chrome/browser/extensions/test_extension_system.cc

Index: chrome/browser/extensions/test_extension_system.cc
diff --git a/chrome/browser/extensions/test_extension_system.cc b/chrome/browser/extensions/test_extension_system.cc
index 3bfaa963393a33ecfe61af1d101b502af6eb8aaf..f0515f761158e14147ccc7a71944ee5cf01a030e 100644
--- a/chrome/browser/extensions/test_extension_system.cc
+++ b/chrome/browser/extensions/test_extension_system.cc
@@ -180,6 +180,13 @@ Blacklist* TestExtensionSystem::blacklist() {
   return blacklist_.get();
 }
 
+const OneShotEvent& TestExtensionSystem::ready() const {
+  return ready_;
+}
+
+void TestExtensionSystem::ExtensionServiceReady() { ready_.Signal(); }
+void TestExtensionSystem::MakeReady() { ready_.Signal(); }

[Matt Perry, 2013/05/16 00:55:50]

Might this cause problems since Signal can only be called once?

[Jeffrey Yasskin, 2013/05/16 00:59:20]

Tests could cause a DCHECK by calling MakeReady() twice, but as long as some
trybots run tests in debug mode, we'll catch that. On the other hand, no tests
are actually using this yet; maybe we don't need it.

+
 // static
 ProfileKeyedService* TestExtensionSystem::Build(
     content::BrowserContext* profile) {