Chromium plumbing for Screen Orientation API orientationchange events.

content/browser/screen_orientation/screen_orientation_dispatcher_host.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 "content/browser/screen_orientation/screen_orientation_dispatcher_host.h"
+
+#include "content/common/screen_orientation_messages.h"
+
+namespace content {
+
+ScreenOrientationDispatcherHost::ScreenOrientationDispatcherHost()
+  : BrowserMessageFilter(ScreenOrientationMsgStart) {
+}
+
+bool ScreenOrientationDispatcherHost::OnMessageReceived(
+    const IPC::Message& message, bool* message_was_ok) {
+  // TODO(mlamouri): we will handle lock and unlock requests here.
+  return true;

[jochen (gone - plz use gerrit), 2014/02/20 16:11:04]

should return false if the message wasn't handled

[mlamouri (slow - plz ping), 2014/02/20 16:32:47]

Gasp. That's what I meant :)

+}
+
+void ScreenOrientationDispatcherHost::OnOrientationChange(
+    int orientation) {
+  // TODO(mlamouri): we might want to have OrientationChangeEvent to pass us
+  // a WebScreenOrientation instead of an int so we can let the backend decide
+  // of the relation between angle and orientation name.
+  Send(new ScreenOrientationMsg_OrientationChange(orientation));

[jochen (gone - plz use gerrit), 2014/02/20 16:11:04]

DCHECK that orientation is a valid value?

What will call OnOrientationChange?

[mlamouri (slow - plz ping), 2014/02/20 16:32:47]

Shouldn't the dispatcher just dispatch? This value is going to go trough so many
layers that I think we could just leave checking the validity at the end. Also,
anyway, this will probably switch from an int to an enum at which point the
validity will be guaranteed.
On Android, the ContentViewCoreImpl will get the ScreenOrientationDispatcherHost
from the RenderProcessHostImpl and call this. I guess other implementations
would do something similar.

+}
+
+}  // namespace content