Mojo-ify implementation of screen orientation locking/unlocking.

content/browser/screen_orientation/screen_orientation_impl.cc

Index: content/browser/screen_orientation/screen_orientation_impl.cc
diff --git a/content/browser/screen_orientation/screen_orientation_impl.cc b/content/browser/screen_orientation/screen_orientation_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f8f28f034573618f32e96c3dc3b1e96b085a520e
--- /dev/null
+++ b/content/browser/screen_orientation/screen_orientation_impl.cc
@@ -0,0 +1,70 @@
+// Copyright 2016 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_impl.h"
+
+#include "base/bind.h"
+#include "content/public/browser/screen_orientation_provider.h"
+#include "content/public/browser/web_contents.h"
+
+namespace content {
+
+using typename ::blink::mojom::ScreenOrientationLockResult;
+
+ScreenOrientationImpl::ScreenOrientationImpl(WebContents* web_contents)
+    : web_contents_(web_contents),
+      binding_(web_contents, this),
+      weak_factory_(this) {
+  provider_.reset(new ScreenOrientationProvider(web_contents));
+}
+
+ScreenOrientationImpl::~ScreenOrientationImpl() = default;
+
+void ScreenOrientationImpl::LockOrientation(
+    blink::WebScreenOrientationLockType orientation,
+    const LockOrientationCallback& callback) {
+  DCHECK(on_result_callback_.is_null());

[blundell, 2016/10/21 18:16:31]

This object is per-WebContents, the same as the old impl was. So you'll still
need to handle the case where a request comes in while a request was already
outstanding. The old impl handled that by simply raising an error on the
previously-outstanding request before handling the new request, so you can do
the same.

[lunalu1, 2016/10/24 16:57:36]

Done.

+  on_result_callback_ = callback;
+
+  if (!provider_) {
+    NotifyLockResult(ScreenOrientationLockResult::
+                         SCREEN_ORIENTATION_LOCK_RESULT_ERROR_NOT_AVAILABLE);
+    return;
+  }
+
+  provider_->LockOrientation(
+      orientation, base::Bind(&ScreenOrientationImpl::NotifyLockResult,
+                              weak_factory_.GetWeakPtr()));
+}
+
+void ScreenOrientationImpl::UnlockOrientation() {
+  // Cancel any pending lock request.
+  NotifyLockResult(ScreenOrientationLockResult::
+                       SCREEN_ORIENTATION_LOCK_RESULT_ERROR_CANCELED);
+
+  if (provider_)
+    provider_->UnlockOrientation();
+}
+
+void ScreenOrientationImpl::NotifyLockResult(
+    ScreenOrientationLockResult result) {
+  if (on_result_callback_.is_null())
+    return;
+  if (result ==
+          ScreenOrientationLockResult::SCREEN_ORIENTATION_LOCK_RESULT_SUCCESS &&
+      binding_.GetCurrentTargetFrame() != web_contents_->GetMainFrame())

[blundell, 2016/10/21 18:16:31]

Why this short-circuit?

[lunalu1, 2016/10/24 16:57:36]

This is done to make sure the lock success messages are received in the same
channel as the ViewMsg_Resize. Please let me know if I did something wrong here.
 

+    return;
+
+  on_result_callback_.Run(result);
+
+  // Reset the callback.
+  on_result_callback_ = LockOrientationCallback();
+}
+
+ScreenOrientationProvider*
+ScreenOrientationImpl::GetScreenOrientationProvider() {
+  return provider_.get();
+}
+
+}  // namespace content