Magnifier: Prevent useless operation in enabling/disabling magnifier.

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.cc
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index fcbddc3ea35630369ac1ec2f63475185ffae85b2..5ae386bbf828831139b6f0941433b47d9bac4d97 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -527,8 +527,7 @@ void ChromeBrowserMainPartsChromeos::PostProfileInit() {
     power_state_override_ = new PowerStateOverride(
         PowerStateOverride::BLOCK_DISPLAY_SLEEP);
   }
-  magnification_manager_.reset(
-      chromeos::MagnificationManager::CreateInstance());
+  chromeos::MagnificationManager::GetInstance()->Initialize();
   chromeos::accessibility::Initialize();
 
   primary_display_switch_observer_.reset(
@@ -627,7 +626,6 @@ void ChromeBrowserMainPartsChromeos::PostMainMessageLoopRun() {
   resume_observer_.reset();
   brightness_observer_.reset();
   output_observer_.reset();

[stevenjb, 2012/12/04 01:35:34]

Having a MagnificationManager instance live past here could cause a number of
subtle shutdown bugs (e.g. accessing a destroyed Profile or ash::Shell). Much
better for code that might accidentally call MagnificationManager::GetInstance()
after this point to crash immediately on a NULL reference.

[yoshiki, 2012/12/04 08:30:20]

I see, I added back removal of the instance.

On 2012/12/04 01:35:34, stevenjb (chromium) wrote:

-  magnification_manager_.reset();
   power_state_override_ = NULL;
 
   // The XInput2 event listener needs to be shut down earlier than when