Fix window focus detection on Linux

On Linux, the FindFocus method from wx simply doesn't work, it would on some environment report that dolphin has the focus while it doesn't have it.  This is why an alternative method has to be used which is to set a focus flag whenever the render frame gets activated.

Source/Core/DolphinWX/Frame.cpp

@@ -504,18 +504,25 @@ void CFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 // Events
 void CFrame::OnActive(wxActivateEvent& event)
 {
+  m_bHasFocus = (event.GetActive() && event.GetEventObject() == m_RenderFrame);
   if (Core::GetState() == Core::CORE_RUN || Core::GetState() == Core::CORE_PAUSE)
   {
-    if (event.GetActive() && event.GetEventObject() == m_RenderFrame)
+    if (m_bHasFocus)
     {
       if (SConfig::GetInstance().bRenderToMain)
         m_RenderParent->SetFocus();
 
+      if (SConfig::GetInstance().m_PauseOnFocusLost && Core::GetState() == Core::CORE_PAUSE)
+        DoPause();
+
       if (SConfig::GetInstance().bHideCursor && Core::GetState() == Core::CORE_RUN)
         m_RenderParent->SetCursor(wxCURSOR_BLANK);
     }
     else
     {
+      if (SConfig::GetInstance().m_PauseOnFocusLost && Core::GetState() == Core::CORE_RUN)
+        DoPause();
+
       if (SConfig::GetInstance().bHideCursor)
         m_RenderParent->SetCursor(wxNullCursor);
     }
@@ -769,27 +776,11 @@ bool CFrame::RendererHasFocus()
 {
   if (m_RenderParent == nullptr)
     return false;
-#ifdef _WIN32
-  HWND window = GetForegroundWindow();
-  if (window == nullptr)
-    return false;
-
-  if (m_RenderFrame->GetHWND() == window)
-    return true;
-#else
-  wxWindow* window = wxWindow::FindFocus();
-  if (window == nullptr)
-    return false;
-  // Why these different cases?
-  if (m_RenderParent == window || m_RenderParent == window->GetParent() ||
-      m_RenderParent->GetParent() == window->GetParent())
-  {
-    return true;
-  }
-#endif
-  return false;
+  return m_bRendererHasFocus;
 }
 
+// Returns true any time any one of our UI windows
+// has the focus, including any dialogs or other windows.
 bool CFrame::UIHasFocus()
 {
   // UIHasFocus should return true any time any one of our UI
@@ -799,8 +790,7 @@ bool CFrame::UIHasFocus()
   // focus. If it's not one of our windows, then it will return
   // null.
 
-  wxWindow* focusWindow = wxWindow::FindFocus();
-  return (focusWindow != nullptr);
+  return m_bHasFocus;
 }
 
 void CFrame::OnGameListCtrlItemActivated(wxListEvent& WXUNUSED(event))
@@ -1139,35 +1129,6 @@ void CFrame::OnMouse(wxMouseEvent& event)
   event.Skip();
 }
 
-void CFrame::OnFocusChange(wxFocusEvent& event)
-{
-  if (SConfig::GetInstance().m_PauseOnFocusLost && Core::IsRunningAndStarted())
-  {
-    if (RendererHasFocus())
-    {
-      if (Core::GetState() == Core::CORE_PAUSE)
-      {
-        Core::SetState(Core::CORE_RUN);
-        if (SConfig::GetInstance().bHideCursor)
-          m_RenderParent->SetCursor(wxCURSOR_BLANK);
-      }
-    }
-    else
-    {
-      if (Core::GetState() == Core::CORE_RUN)
-      {
-        Core::SetState(Core::CORE_PAUSE);
-        if (SConfig::GetInstance().bHideCursor)
-          m_RenderParent->SetCursor(wxNullCursor);
-        Core::UpdateTitle();
-      }
-    }
-    UpdateGUI();
-  }
-
-  event.Skip();
-}
-
 void CFrame::DoFullscreen(bool enable_fullscreen)
 {
   if (g_Config.bExclusiveMode && Core::GetState() == Core::CORE_PAUSE)

Source/Core/DolphinWX/Frame.h

@@ -158,6 +158,7 @@ private:
   bool m_bNoDocking = false;
   bool m_bGameLoading = false;
   bool m_bClosing = false;
+  bool m_bHasFocus = false;
   bool m_confirmStop = false;
   bool m_tried_graceful_shutdown = false;
   int m_saveSlot = 1;
@@ -306,8 +307,6 @@ private:
   void OnKeyDown(wxKeyEvent& event);  // Keyboard
   void OnMouse(wxMouseEvent& event);  // Mouse
 
-  void OnFocusChange(wxFocusEvent& event);
-
   void OnHostMessage(wxCommandEvent& event);
 
   void OnMemcard(wxCommandEvent& event);  // Misc

Source/Core/DolphinWX/FrameTools.cpp

@@ -733,8 +733,6 @@ void CFrame::StartGame(const std::string& filename)
     wxTheApp->Bind(wxEVT_MIDDLE_DOWN, &CFrame::OnMouse, this);
     wxTheApp->Bind(wxEVT_MIDDLE_UP, &CFrame::OnMouse, this);
     wxTheApp->Bind(wxEVT_MOTION, &CFrame::OnMouse, this);
-    wxTheApp->Bind(wxEVT_SET_FOCUS, &CFrame::OnFocusChange, this);
-    wxTheApp->Bind(wxEVT_KILL_FOCUS, &CFrame::OnFocusChange, this);
     m_RenderParent->Bind(wxEVT_SIZE, &CFrame::OnRenderParentResize, this);
   }
 }
@@ -926,6 +924,8 @@ void CFrame::OnStopped()
     m_RenderFrame->SetWindowStyle(m_RenderFrame->GetWindowStyle() & ~wxSTAY_ON_TOP);
   }
   m_RenderParent = nullptr;
+  m_bRendererHasFocus = false;
+  m_RenderFrame = nullptr;
 
   // Clean framerate indications from the status bar.
   GetStatusBar()->SetStatusText(" ", 0);