Refactors DeviceOrientation to make it more extensible

content/browser/device_orientation/orientation_message_filter.cc

 // Copyright (c) 2012 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/device_orientation/orientation_message_filter.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/device_orientation/orientation.h"
 #include "content/browser/device_orientation/provider.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
@@ skipping 11 matching lines @@
 }
 
 class OrientationMessageFilter::ObserverDelegate
     : public base::RefCounted<ObserverDelegate>, public Provider::Observer {
  public:
     // Create ObserverDelegate that observes provider and forwards updates to
     // render_view_id in process_id.
     // Will stop observing provider when destructed.
     ObserverDelegate(Provider* provider,
                      int render_view_id,
-                     IPC::Sender* sender);
+                     IPC::Sender* sender,
+                     DeviceData::DeviceDataType device_data_type);
 
     // From Provider::Observer.
-    virtual void OnOrientationUpdate(const Orientation& orientation);
+    virtual void OnDeviceDataUpdate(const DeviceData* device_data);
 
  private:
   friend class base::RefCounted<ObserverDelegate>;
   virtual ~ObserverDelegate();
 
   scoped_refptr<Provider> provider_;
   int render_view_id_;
   IPC::Sender* sender_;  // Weak pointer.
 
   DISALLOW_COPY_AND_ASSIGN(ObserverDelegate);
 };
 
 OrientationMessageFilter::ObserverDelegate::ObserverDelegate(Provider* provider,
-                                                  int render_view_id,
-                                                  IPC::Sender* sender)
-    : provider_(provider),
-      render_view_id_(render_view_id),
-      sender_(sender) {
+    int render_view_id, IPC::Sender* sender,
+    DeviceData::DeviceDataType device_data_type)
+  : provider_(provider),

[bulach, 2012/07/12 10:43:27]

nit: I think the initializer list needs to be indented by 4..

[aousterh, 2012/07/12 17:13:57]

Done.

+    render_view_id_(render_view_id),
+    sender_(sender) {
   provider_->AddObserver(this);
+  device_data_type_ = device_data_type;
 }
 
 OrientationMessageFilter::ObserverDelegate::~ObserverDelegate() {
   provider_->RemoveObserver(this);
 }
 
-void OrientationMessageFilter::ObserverDelegate::OnOrientationUpdate(
-    const Orientation& orientation) {
+void OrientationMessageFilter::ObserverDelegate::OnDeviceDataUpdate(
+    const DeviceData* device_data) {
   DeviceOrientationMsg_Updated_Params params;
-  params.can_provide_alpha = orientation.can_provide_alpha();
-  params.alpha = orientation.alpha();
-  params.can_provide_beta = orientation.can_provide_beta();
-  params.beta = orientation.beta();
-  params.can_provide_gamma = orientation.can_provide_gamma();
-  params.gamma = orientation.gamma();
-  params.can_provide_absolute = orientation.can_provide_absolute();
-  params.absolute = orientation.absolute();
+
+  const Orientation* orientation = static_cast<const Orientation*>(device_data);

[bulach, 2012/07/12 10:43:27]

hmm... I'm not a 100% of this suggestion, but here we go.. :)
what if we had a virtual Message* CreateIPCMessage() const; in DeviceData
itself?
then this layer would be completely transparent to it...

[aousterh, 2012/07/12 17:13:57]

Done.

+  const Orientation empty_orientation;
+  if (orientation == NULL)
+    orientation = &empty_orientation;
+
+  params.can_provide_alpha = orientation->can_provide_alpha();
+  params.alpha = orientation->alpha();
+  params.can_provide_beta = orientation->can_provide_beta();
+  params.beta = orientation->beta();
+  params.can_provide_gamma = orientation->can_provide_gamma();
+  params.gamma = orientation->gamma();
+  params.can_provide_absolute = orientation->can_provide_absolute();
+  params.absolute = orientation->absolute();
 
   sender_->Send(new DeviceOrientationMsg_Updated(render_view_id_, params));
 }
 
 bool OrientationMessageFilter::OnMessageReceived(const IPC::Message& message,
                                       bool* message_was_ok) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP_EX(OrientationMessageFilter, message, *message_was_ok)
     IPC_MESSAGE_HANDLER(DeviceOrientationHostMsg_StartUpdating, OnStartUpdating)
     IPC_MESSAGE_HANDLER(DeviceOrientationHostMsg_StopUpdating, OnStopUpdating)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void OrientationMessageFilter::OnStartUpdating(int render_view_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   if (!provider_)
     provider_ = Provider::GetInstance();
 
   observers_map_[render_view_id] = new ObserverDelegate(provider_,
-                                                        render_view_id,
-                                                        this);
+      render_view_id, this, DeviceData::kDeviceOrientationData);
 }
 
 void OrientationMessageFilter::OnStopUpdating(int render_view_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   observers_map_.erase(render_view_id);
 }
 
 }  // namespace device_orientation