Create Mojo service for locking/unlocking screen orientation.

content/browser/screen_orientation/screen_orientation_service_impl.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_service_impl.h"
+
+#include "base/bind.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/public/browser/screen_orientation_provider.h"
+
+namespace content {
+
+// static
+void ScreenOrientationServiceImpl::Create(
+    WebContents* web_contents,
+    mojo::InterfaceRequest<ScreenOrientationService> request) {
+  BindToRequest(new ScreenOrientationServiceImpl(web_contents), &request);
+}
+
+ScreenOrientationServiceImpl::ScreenOrientationServiceImpl(
+    WebContents* web_contents)
+    : context_(static_cast<WebContentsImpl*>(web_contents)
+                   ->screen_orientation_context()),

[qsr, 2014/09/22 13:01:48]

The -> should be on the previous line.

+      provider_(ScreenOrientationProvider::Create(

[qsr, 2014/09/22 13:01:48]

As discussed live, maybe we want the provider to be per-webcontent given that a
single lock request can be live at any time.

[blundell, 2014/09/22 13:21:54]

Yes, I agree. The provider can be per-WebContents and can have a virtual
OnOrientationChange() method that is what ContentViewCoreImpl will call
directly. Rather than the provider taking in a callback in its constructor, it
can take in a callback in its LockOrientation() method. The
ScreenOrientationContext class that I introduced can then go back away. This
design seems like it will be cleaner.

Mounir, does this make sense to you?

+          base::Bind(&ScreenOrientationServiceImpl::NotifyLockResult,
+                     base::Unretained(this)),
+          web_contents)) {
+  context_->AddObserver(this);
+}
+
+ScreenOrientationServiceImpl::~ScreenOrientationServiceImpl() {
+  context_->RemoveObserver(this);
+}
+
+void ScreenOrientationServiceImpl::NotifyLockResult(
+    ScreenOrientationLockResult result) {
+  if (on_result_callback_.is_null())
+    return;
+
+  on_result_callback_.Run(result);
+
+  // Reset the callback.
+  on_result_callback_ = mojo::Callback<void(ScreenOrientationLockResult)>();
+}
+
+void ScreenOrientationServiceImpl::OnScreenOrientationChange() {
+  if (provider_)
+    provider_->OnOrientationChange();
+}
+
+void ScreenOrientationServiceImpl::OnNewLockRequest() {
+  // Cancel any pending lock request.
+  NotifyLockResult(SCREEN_ORIENTATION_LOCK_RESULT_ERROR_CANCELED);
+}
+
+void ScreenOrientationServiceImpl::LockOrientation(
+    ScreenOrientationLockType lock_type,
+    const mojo::Callback<void(ScreenOrientationLockResult)>& callback) {
+  context_->OnNewLockRequest();
+
+  DCHECK(on_result_callback_.is_null());
+  on_result_callback_ = callback;
+
+  if (!provider_) {
+    NotifyLockResult(SCREEN_ORIENTATION_LOCK_RESULT_ERROR_NOT_AVAILABLE);
+    return;
+  }
+
+  provider_->LockOrientation(lock_type);
+}
+
+void ScreenOrientationServiceImpl::UnlockOrientation() {
+  // Cancel any pending lock request.
+  NotifyLockResult(SCREEN_ORIENTATION_LOCK_RESULT_ERROR_CANCELED);
+
+  if (provider_)
+    provider_->UnlockOrientation();
+}
+
+}  // namespace content