Fix Up SingletonHwnd Observer Lifetime Issues

ui/gfx/sys_color_change_listener.cc

Index: ui/gfx/sys_color_change_listener.cc
diff --git a/ui/gfx/sys_color_change_listener.cc b/ui/gfx/sys_color_change_listener.cc
index 0e5008a66e08a1e0607f08518656829f74b93315..6a0c3aabebcc57363353ab22b96a5bac857f36d2 100644
--- a/ui/gfx/sys_color_change_listener.cc
+++ b/ui/gfx/sys_color_change_listener.cc
@@ -9,6 +9,8 @@
 #endif
 
 #include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "ui/gfx/color_utils.h"
@@ -49,7 +51,7 @@ bool IsInvertedColorScheme() {
 }
 
 #if defined(OS_WIN)
-class SysColorChangeObserver : public gfx::SingletonHwnd::Observer {
+class SysColorChangeObserver {
  public:
   static SysColorChangeObserver* GetInstance();
 
@@ -62,12 +64,10 @@ class SysColorChangeObserver : public gfx::SingletonHwnd::Observer {
   SysColorChangeObserver();
   virtual ~SysColorChangeObserver();
 
-  void OnWndProc(HWND hwnd,
-                 UINT message,
-                 WPARAM wparam,
-                 LPARAM lparam) override;
+  void OnSysColorChange(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);
 
   ObserverList<SysColorChangeListener> listeners_;
+  gfx::SingletonHwnd::Observer singletonHwndObserver_;
 };
 
 // static
@@ -76,12 +76,12 @@ SysColorChangeObserver* SysColorChangeObserver::GetInstance() {
 }
 
 SysColorChangeObserver::SysColorChangeObserver() {
-  gfx::SingletonHwnd::GetInstance()->AddObserver(this);
+  singletonHwndObserver_.SetWndProc(
+      base::Bind(&SysColorChangeObserver::OnSysColorChange,
+                 base::Unretained(this)));
 }
 
-SysColorChangeObserver::~SysColorChangeObserver() {
-  gfx::SingletonHwnd::GetInstance()->RemoveObserver(this);
-}
+SysColorChangeObserver::~SysColorChangeObserver() {}
 
 void SysColorChangeObserver::AddListener(SysColorChangeListener* listener) {
   listeners_.AddObserver(listener);
@@ -91,10 +91,10 @@ void SysColorChangeObserver::RemoveListener(SysColorChangeListener* listener) {
   listeners_.RemoveObserver(listener);
 }
 
-void SysColorChangeObserver::OnWndProc(HWND hwnd,
-                                       UINT message,
-                                       WPARAM wparam,
-                                       LPARAM lparam) {
+void SysColorChangeObserver::OnSysColorChange(HWND hwnd,
+                                              UINT message,
+                                              WPARAM wparam,
+                                              LPARAM lparam) {
   if (message == WM_SYSCOLORCHANGE ||
       (message == WM_SETTINGCHANGE && wparam == SPI_SETHIGHCONTRAST)) {
     UpdateInvertedColorScheme();