Prevent duplicate concurrent installs of the same extension

chrome/browser/extensions/active_install_data.cc

Index: chrome/browser/extensions/active_install_data.cc
diff --git a/chrome/browser/extensions/active_install_data.cc b/chrome/browser/extensions/active_install_data.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f9c9a0c878149c56fac166a0962fcc808983d146
--- /dev/null
+++ b/chrome/browser/extensions/active_install_data.cc
@@ -0,0 +1,58 @@
+// 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 "chrome/browser/extensions/active_install_data.h"
+
+#include "chrome/browser/extensions/install_tracker.h"
+
+namespace extensions {
+
+// ActiveInstallData:
+
+ActiveInstallData::ActiveInstallData()
+    : percent_downloaded(0), is_ephemeral(false) {
+}
+
+ActiveInstallData::ActiveInstallData(const std::string& extension_id)
+    : extension_id(extension_id), percent_downloaded(0), is_ephemeral(false) {
+}
+
+// ScopedActiveInstall:
+
+ScopedActiveInstall::ScopedActiveInstall(InstallTracker* tracker,
+                                         const ActiveInstallData& install_data)
+    : tracker_(tracker),
+      tracker_observer_(this),
+      extension_id_(install_data.extension_id) {
+  Init();
+  tracker_->AddActiveInstall(install_data);
+}
+
+ScopedActiveInstall::ScopedActiveInstall(InstallTracker* tracker,
+                                         const std::string& extension_id)
+    : tracker_(tracker), tracker_observer_(this), extension_id_(extension_id) {
+  Init();
+}
+
+ScopedActiveInstall::~ScopedActiveInstall() {
+  if (tracker_)
+    tracker_->RemoveActiveInstall(extension_id_);
+}
+
+void ScopedActiveInstall::CancelDeregister() {
+  tracker_observer_.RemoveAll();
+  tracker_ = NULL;
+}
+
+void ScopedActiveInstall::Init() {
+  DCHECK(!extension_id_.empty());
+  DCHECK(tracker_);
+  tracker_observer_.Add(tracker_);
+}
+
+void ScopedActiveInstall::OnShutdown() {
+  CancelDeregister();
+}
+
+}  // namespace extensions