Fix several issues around fullscreen Mac plugins:...

chrome/browser/plugin_process_host.h

Index: chrome/browser/plugin_process_host.h
===================================================================
--- chrome/browser/plugin_process_host.h	(revision 27721)
+++ chrome/browser/plugin_process_host.h	(working copy)
@@ -112,6 +112,13 @@
   void OnMapNativeViewId(gfx::NativeViewId id, gfx::PluginWindowHandle* output);
 #endif
 
+#if defined(OS_MACOSX)
+  void OnPluginSelectWindow(uint32 window_id, gfx::Rect window_rect);
+  void OnPluginShowWindow(uint32 window_id, gfx::Rect window_rect);
+  void OnPluginHideWindow(uint32 window_id, gfx::Rect window_rect);
+  void OnPluginDisposeWindow(uint32 window_id, gfx::Rect window_rect);
+#endif
+
   virtual bool CanShutdown() { return sent_requests_.empty(); }
 
   struct ChannelRequest {
@@ -143,6 +150,10 @@
   // Tracks plugin parent windows created on the UI thread.
   std::set<HWND> plugin_parent_windows_set_;
 #endif
+#if defined(OS_MACOSX)
+  // Tracks plugin windows currently visible
+  std::set<uint32> plugin_visible_windows_set_;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(PluginProcessHost);
 };