Chromium plumbing for Screen Orientation API lock/unlock.

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/browser/screen_orientation/screen_orientation_provider.h"
 #include "content/common/screen_orientation_messages.h"
 
 namespace content {
 
 ScreenOrientationDispatcherHost::ScreenOrientationDispatcherHost() {
+  if (!provider_.get())
+    provider_.reset(CreateProvider());
+}
+
+ScreenOrientationDispatcherHost::~ScreenOrientationDispatcherHost() {
 }
 
 bool ScreenOrientationDispatcherHost::OnMessageReceived(
     const IPC::Message& message, bool* message_was_ok) {
-  // TODO(mlamouri): we will handle lock and unlock requests here.
-  return false;
+  bool handled = true;
+
+  IPC_BEGIN_MESSAGE_MAP_EX(ScreenOrientationDispatcherHost,
+                           message,
+                           *message_was_ok)
+    IPC_MESSAGE_HANDLER(ScreenOrientationMsg_Lock, OnLockRequest)
+    IPC_MESSAGE_HANDLER(ScreenOrientationMsg_Unlock, OnUnlockRequest)

[Cris Neckar, 2014/02/24 21:02:28]

Currently sending these messages will result in a crash. You will need to
request another IPC message review when you implement
ScreenOrientationProvider::LockOrientation and UnlockOrientation... I would
really prefer that until then you don't dereference null and cause a browser
crash.

[mlamouri (slow - plz ping), 2014/02/24 21:47:50]

I'm not sure I understand wyh that would crash. Before calling |LockOrientation|
and |UnlockOrientation| on |provider_|, I check if |provider_.get()| is null. It
seems that this is a very common pattern for Android-only features: the provider
is null unless OS_ANDROID is defined. Did I miss something obvious here?

[Cris Neckar, 2014/02/24 22:00:04]

oh my mistake I was reading too quickly. Saw the check in the constructor and
then you reset it to null. 

Please do request another review when you implement the handler in the provider
though.

+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+
+  return handled;
 }
 
 void ScreenOrientationDispatcherHost::OnOrientationChange(
     blink::WebScreenOrientation orientation) {
   Send(new ScreenOrientationMsg_OrientationChange(orientation));
 }
 
+void ScreenOrientationDispatcherHost::SetProviderForTests(
+    ScreenOrientationProvider* provider) {
+  provider_.reset(provider);
+}
+
+void ScreenOrientationDispatcherHost::OnLockRequest(
+    blink::WebScreenOrientations orientations) {
+  if (!provider_.get())
+    return;
+
+  provider_->LockOrientation(orientations);

[Cris Neckar, 2014/02/24 21:02:28]

remove this until you actually implement it.

You will also need another IPC review from me or another security reviewer on
the CL that implements these.

+}
+
+void ScreenOrientationDispatcherHost::OnUnlockRequest() {
+  if (!provider_.get())
+    return;
+
+  provider_->UnlockOrientation();

[Cris Neckar, 2014/02/24 21:02:28]

ditto

+}
+
+// static
+ScreenOrientationProvider* ScreenOrientationDispatcherHost::CreateProvider() {
+  return NULL;
+}
+
 }  // namespace content