Split Android-specific dependency from BackgroundLoaderOffliner. Create a subfolder of c/b/offline_…

chrome/browser/offline_pages/android/load_termination_listener_impl.cc

Index: chrome/browser/offline_pages/android/load_termination_listener_impl.cc
diff --git a/chrome/browser/offline_pages/android/load_termination_listener_impl.cc b/chrome/browser/offline_pages/android/load_termination_listener_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3bdb1101f2bc87c33006a112b9233a55b612b83e
--- /dev/null
+++ b/chrome/browser/offline_pages/android/load_termination_listener_impl.cc
@@ -0,0 +1,35 @@
+// Copyright 2017 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/offline_pages/android/load_termination_listener_impl.h"
+
+#include "base/android/application_status_listener.h"
+#include "base/logging.h"
+#include "base/sys_info.h"
+
+namespace offline_pages {
+
+LoadTerminationListenerImpl::LoadTerminationListenerImpl()
+    : weak_ptr_factory_(this) {
+  if (base::SysInfo::IsLowEndDevice()) {
+    app_listener_ = base::MakeUnique<base::android::ApplicationStatusListener>(
+        base::Bind(&LoadTerminationListenerImpl::OnApplicationStateChange,
+                   weak_ptr_factory_.GetWeakPtr()));

[dewittj, 2017/05/24 23:24:40]

q: technically could this be base::Unretained(this) since we own the
app_listener_?

[Dmitry Titov, 2017/05/25 23:24:13]

It indeed would be, in this specific case. I'm hesitant to switch to Unretained
though because it feels as more load on casual reader to verify that lifetimes
are correct. In this case, it's a non-local lookup into the code... Let me know
if you think there is a reason to switch!

+  }
+}
+
+LoadTerminationListenerImpl::~LoadTerminationListenerImpl() {
+}
+
+void LoadTerminationListenerImpl::OnApplicationStateChange(
+    base::android::ApplicationState application_state) {
+  if (offliner_ &&
+      application_state ==
+          base::android::APPLICATION_STATE_HAS_RUNNING_ACTIVITIES) {
+    DVLOG(1) << "App became foreground, canceling current offlining request";
+    offliner_->TerminateLoadIfInProgress();
+  }
+}
+
+}  // namespace offline_pages