Add a test helper class for ExtensionRegistry.

extensions/browser/extension_test_registry_observer.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/browser/extension_test_registry_observer.h"
+
+#include "base/run_loop.h"
+
+namespace extensions {
+
+ExtensionTestRegistryObserver::ExtensionTestRegistryObserver(
+    ExtensionRegistry* registry)
+    : waiting_for_installed_(false),
+      received_installed_(false),
+      runner_installed_(new content::MessageLoopRunner()),
+      waiting_for_uninstalled_(false),
+      received_uninstalled_(false),
+      runner_uninstalled_(new content::MessageLoopRunner()),
+      extension_registry_observer_(this) {
+  extension_registry_observer_.Add(registry);
+}
+
+ExtensionTestRegistryObserver::~ExtensionTestRegistryObserver() {
+}
+
+void ExtensionTestRegistryObserver::WaitForExtensionUninstalled() {
+  if (received_uninstalled_)
+    return;
+
+  waiting_for_uninstalled_ = true;
+  runner_uninstalled_->Run();

[not at google - send to devlin, 2014/06/15 21:20:16]

it would be nice to factor all of this shared state into a single class, that
is, the tuple of (waiting, received, runner). For example,

=== extension_test_registry_observer.h
class Waiter;
scoped_ptr<Waiter> installed_waiter_;
scoped_ptr<Waiter> uninstalled_waiter_;

=== extension_test_registry_observer.cc
class ExtensionTestRegistryObserver::Waiter {
 public:
  Waiter(...) : ... {}

  void Wait(...) {
  }

  void OnObserved(...) {
  }

 private:
  ...
};

ExtensionTestRegistryObserver::ExtensionTestRegistryObserver(...)
    : ..., installed_waiter_(new Waiter()), uninstalled_watier_(new Waiter()) {
}

void ExtensionTestRegistryObserver::WaitForExtensionInstalled() {
  installed_waiter_->Wait();
}

void ExtensionTestRegistryObserver::OnExtensionWillBeInstalled(...) {
  installed_waiter_->OnObserved();
}

[limasdf, 2014/06/16 18:58:53]

Done.

+}
+
+void ExtensionTestRegistryObserver::WaitForExtensionInstalled() {
+  if (received_installed_)
+    return;
+
+  waiting_for_installed_ = true;
+  runner_installed_->Run();
+}
+
+void ExtensionTestRegistryObserver::OnExtensionWillBeInstalled(
+    content::BrowserContext* browser_context,
+    const Extension* extension,
+    bool is_update,
+    bool from_ephemeral,
+    const std::string& old_name) {
+  received_installed_ = true;
+  if (waiting_for_installed_) {
+    waiting_for_installed_ = false;
+    runner_installed_->Quit();
+  }
+}
+
+void ExtensionTestRegistryObserver::OnExtensionUninstalled(
+    content::BrowserContext* browser_context,
+    const Extension* extension) {
+  received_uninstalled_ = true;
+  if (waiting_for_uninstalled_) {
+    waiting_for_uninstalled_ = false;
+    runner_uninstalled_->Quit();
+  }
+}
+
+}  // namespace extensions