Add initial support for native Linux desktop notifications

chrome/browser/notifications/notification_platform_bridge_linux.cc

+// 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/notifications/notification_platform_bridge_linux.h"
+
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/notifications/notification.h"
+
+namespace {
+
+const char kFreedesktopNotificationsName[] = "org.freedesktop.Notifications";
+const char kFreedesktopNotificationsPath[] = "/org/freedesktop/Notifications";
+
+}  // anonymous namespace

[Lei Zhang, 2017/04/04 07:47:21]

s/anonymous //

[Tom (Use chromium acct), 2017/04/04 21:47:10]

Done.

+
+// static
+NotificationPlatformBridge* NotificationPlatformBridge::Create() {
+  GDBusProxy* notification_proxy = g_dbus_proxy_new_for_bus_sync(
+      G_BUS_TYPE_SESSION,
+      static_cast<GDBusProxyFlags>(G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES |
+                                   G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS |
+                                   G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START),
+      nullptr, kFreedesktopNotificationsName, kFreedesktopNotificationsPath,
+      kFreedesktopNotificationsName, nullptr, nullptr);
+  if (notification_proxy)

[Lei Zhang, 2017/04/04 07:47:21]

braces, or

if (!notification_proxy)
  return nullptr;
return new NotificationPlatformBridgeLinux(...);

[Tom (Use chromium acct), 2017/04/04 21:47:10]

Done.

+    return new NotificationPlatformBridgeLinux(
+        message_center::MessageCenter::Get(), notification_proxy);
+  return nullptr;

[Peter Beverloo, 2017/04/04 13:34:46]

If my understanding is correct, this means that
NotificationPlatformBridge::Create() will return a nullptr when the platform
does not provide the freedesktop notification service, right?

If so, why would this class need a pointer to the message center? Ideally the
implementation of it, once created, would just assume that functionality is
available w/o additional bail-out checks.

(We experimented with falling back to the message_center when unsupported
notification features were requested, e.g. progress bars, but that created for a
terrible user experience.)

[Tom (Use chromium acct), 2017/04/04 21:47:10]

Yes
Removed message_center_.  I thought I needed it to call
MessageCenter::ClickOnNotification et al.  How does NotificationPlatformBridge
handle clicks?

[Peter Beverloo, 2017/04/04 21:55:09]

It's still a bit cumbersome, but following Chromium's rule-of-three (code
duplication) I'll pick this up soonish and generalize the entire flow between
the three platforms that now support native notifications.

    1) Load the profile based on |profile_id| and |is_incognito|.

https://cs.chromium.org/chromium/src/chrome/browser/notifications/notificatio...

    2) Call NativeNotificationDisplayService::ProcessNotificationOperation()

https://cs.chromium.org/chromium/src/chrome/browser/notifications/notificatio...

+}
+
+NotificationPlatformBridgeLinux::NotificationPlatformBridgeLinux(
+    message_center::MessageCenter* message_center,
+    GDBusProxy* notification_proxy)
+    : message_center_(message_center), notification_proxy_(notification_proxy) {
+  (void)message_center_;  // Silence the unused warning.

[Lei Zhang, 2017/04/04 07:47:21]

Is this because we plan to use |message_center_| in the NOTIMPLEMENTED()
methods?

[Tom (Use chromium acct), 2017/04/04 21:47:10]

Yes, but I think my understanding of MessageCenter was wrong, so I removed it

+}
+
+NotificationPlatformBridgeLinux::~NotificationPlatformBridgeLinux() {
+  g_object_unref(notification_proxy_);
+}
+
+void NotificationPlatformBridgeLinux::Display(
+    NotificationCommon::Type notification_type,
+    const std::string& notification_id,
+    const std::string& profile_id,
+    bool is_incognito,
+    const Notification& notification) {
+  // TODO(thomasanderson): Add a complete implementation.
+  g_dbus_proxy_call(
+      notification_proxy_, "Notify",
+      g_variant_new("(susssasa{sv}i)", "", 0, "",
+                    base::UTF16ToUTF8(notification.title()).c_str(),
+                    base::UTF16ToUTF8(notification.message()).c_str(), nullptr,
+                    nullptr, -1),
+      G_DBUS_CALL_FLAGS_NONE, -1, nullptr, nullptr, nullptr);
+}
+
+void NotificationPlatformBridgeLinux::Close(
+    const std::string& profile_id,
+    const std::string& notification_id) {
+  NOTIMPLEMENTED();
+}
+
+void NotificationPlatformBridgeLinux::GetDisplayed(
+    const std::string& profile_id,
+    bool incognito,
+    const DisplayedNotificationsCallback& callback) const {
+  NOTIMPLEMENTED();

[Peter Beverloo, 2017/04/04 13:34:46]

nit: the |callback| has an argument to indicate whether it's supported.

    callback.Run(base::MakeUnique<std::set<std::string>>(), false /*
supports_synchronization */);

[Tom (Use chromium acct), 2017/04/04 21:47:10]

Done.

+}