OSX: Remove some nsnotificationcenter observers more reliably.

chrome/browser/autocomplete/autocomplete_edit_view_mac.mm

Index: chrome/browser/autocomplete/autocomplete_edit_view_mac.mm
diff --git a/chrome/browser/autocomplete/autocomplete_edit_view_mac.mm b/chrome/browser/autocomplete/autocomplete_edit_view_mac.mm
index 69a1b4ee32dd4578503bcc95eef4d7763fa2c325..de894c677bd87090cf1219c08fc9487c2d40654b 100644
--- a/chrome/browser/autocomplete/autocomplete_edit_view_mac.mm
+++ b/chrome/browser/autocomplete/autocomplete_edit_view_mac.mm
@@ -184,9 +184,6 @@ AutocompleteEditViewMac::~AutocompleteEditViewMac() {
   // Disconnect field_ from edit_helper_ so that we don't get calls
   // after destruction.
   [field_ setDelegate:nil];
-
-  // Disconnect notifications so they don't signal a dead object.
-  [[NSNotificationCenter defaultCenter] removeObserver:edit_helper_];
 }
 
 void AutocompleteEditViewMac::SaveStateToTab(TabContents* tab) {
@@ -717,6 +714,11 @@ std::wstring AutocompleteEditViewMac::GetClipboardText(Clipboard* clipboard) {
   return self;
 }
 
+- (void)dealloc {
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+}
+
 - (BOOL)control:(NSControl*)control
        textView:(NSTextView*)textView doCommandBySelector:(SEL)cmd {
   // Don't intercept up/down-arrow if the popup isn't open.