Reduce the fullscreen window height by 1px on activation loss.

ui/views/win/hwnd_message_handler.h

Index: ui/views/win/hwnd_message_handler.h
diff --git a/ui/views/win/hwnd_message_handler.h b/ui/views/win/hwnd_message_handler.h
index 4b7ab4179a0d2ff5e937d9ff4508ace27043c652..0dc180677b8a54a2085d9cceadb707abb8e395d8 100644
--- a/ui/views/win/hwnd_message_handler.h
+++ b/ui/views/win/hwnd_message_handler.h
@@ -206,6 +206,16 @@ class VIEWS_EXPORT HWNDMessageHandler :
   // Updates the window style to reflect whether it can be resized or maximized.
   void SizeConstraintsChanged();
 
+  // Setter getter combination for a background fullscreen window, i.e a
+  // fullscreen window which lost activation.
+  void set_background_fullscreen_hack(bool set_background_fullscreen) {
+    background_fullscreen_hack_ = set_background_fullscreen;
+  }
+
+  bool background_fullscreen_hack() const {
+    return background_fullscreen_hack_;
+  }
+
  private:
   typedef std::set<DWORD> TouchIDs;
 
@@ -255,7 +265,10 @@ class VIEWS_EXPORT HWNDMessageHandler :
 
   // Called after the WM_ACTIVATE message has been processed by the default
   // windows procedure.
-  void PostProcessActivateMessage(int activation_state, bool minimized);
+  void PostProcessActivateMessage(
+      int activation_state,
+      bool minimized,
+      HWND window_gaining_or_losing_activation);
 
   // Enables disabled owner windows that may have been disabled due to this
   // window's modality.
@@ -632,6 +645,10 @@ class VIEWS_EXPORT HWNDMessageHandler :
   // Defaults to false.
   bool left_button_down_on_caption_;
 
+  // Set to true if the window is a background fullscreen window, i.e a
+  // fullscreen window which lost activation. Defaults to false.
+  bool background_fullscreen_hack_;
+
   // The WeakPtrFactories below must occur last in the class definition so they
   // get destroyed last.