Implemented new channel switcher UI.

chromeos/dbus/update_engine_client.h

Index: chromeos/dbus/update_engine_client.h
diff --git a/chromeos/dbus/update_engine_client.h b/chromeos/dbus/update_engine_client.h
index 914094e162663d9e88ae53d6cd928682283cada0..4c3d20228439875dcc5072bcc65371387b53e3dc 100644
--- a/chromeos/dbus/update_engine_client.h
+++ b/chromeos/dbus/update_engine_client.h
@@ -14,7 +14,7 @@
 
 namespace dbus {
 class Bus;
-}  // namespace
+}
 
 namespace chromeos {
 
@@ -87,6 +87,7 @@ class CHROMEOS_EXPORT UpdateEngineClient {
   // Reboots if update has been performed.
   virtual void RebootAfterUpdate() = 0;
 
+  // DEPRECATED: Use SetChannel instead.
   // Requests to set the release track (channel). |track| should look like
   // "beta-channel" or "dev-channel".
   virtual void SetReleaseTrack(const std::string& track) = 0;
@@ -95,6 +96,11 @@ class CHROMEOS_EXPORT UpdateEngineClient {
   // - string: the release track name like "beta-channel".
   typedef base::Callback<void(const std::string&)> GetReleaseTrackCallback;
 
+  // Called once GetChannel() is complete. Takes one parameter;
+  // - string: the channel name like "beta-channel".
+  typedef base::Callback<void(const std::string&)> GetChannelCallback;

[satorux1, 2013/06/24 17:21:12]

Please add a parameter name:

typedef base::Callback<void(const std::string& channel_name)>

[ygorshenin1, 2013/06/24 17:50:35]

Done.

+
+  // DEPRECATED: Use GetChannel() instead.
   // Requests to get the release track and calls |callback| with the
   // release track (channel). On error, calls |callback| with an empty
   // string.
@@ -106,6 +112,27 @@ class CHROMEOS_EXPORT UpdateEngineClient {
   // that need this information.
   virtual Status GetLastStatus() = 0;
 
+  // Changes the current channel of the device to the target
+  // channel. If the target channel is a less stable channel than the
+  // current channel, then the channel change happens immediately (at
+  // the next update check).  If the target channel is a more stable
+  // channel, then if |is_powerwash_allowed| is set to true, then also
+  // the change happens immediately but with a powerwash if
+  // required. Otherwise, the change takes effect eventually (when the
+  // version on the target channel goes above the version number of
+  // what the device currently has). |target_channel| should look like
+  // "dev-channel", "beta-channel" or "stable-channel".
+  virtual void SetChannel(const std::string& target_channel,
+                          bool is_powerwash_allowed) = 0;

[satorux1, 2013/06/24 17:21:12]

boolean parameters like this often make callers hard to read:

  SetChannel(channel, true);  // true of what?

You might want to define an enum like POWERWASH_NONE and POWERWASH_ALLOWED

However, looking at the caller, this parameter comes from
VersionUpdaterCros::SetChannel(), which also takes a boolean parameter. Then,
introducing an enum just for this function wouldn't make sense...

[ygorshenin1, 2013/06/24 17:50:35]

We're planning to introduce an enum instead of strings for channel names and,
possibly, symbolic constants instead of booleans. But as we're in hurry, this
will be done in a separate CL.

On 2013/06/24 17:21:12, satorux1 wrote:

+
+  // If |get_current_channel| is set to true, calls |callback| with
+  // the name of the channel that the device is currently
+  // on. Otherwise, it calls it with the name of the channel the
+  // device is supposed to be (in case of a pending channel
+  // change). On error, calls |callback| with an empty string.
+  virtual void GetChannel(bool get_current_channel,
+                          const GetChannelCallback& callback) = 0;
+
   // Returns an empty UpdateCheckCallback that does nothing.
   static UpdateCheckCallback EmptyUpdateCheckCallback();