Fix crash in ProfileMenuController::validateMenuItem.

chrome/browser/ui/cocoa/profiles/profile_menu_controller.mm

Index: chrome/browser/ui/cocoa/profiles/profile_menu_controller.mm
diff --git a/chrome/browser/ui/cocoa/profiles/profile_menu_controller.mm b/chrome/browser/ui/cocoa/profiles/profile_menu_controller.mm
index 437bed15fe87fef70434fae95bd5058c3048dc8a..5ee576fe66a875dec003d89759ba4a46724199e2 100644
--- a/chrome/browser/ui/cocoa/profiles/profile_menu_controller.mm
+++ b/chrome/browser/ui/cocoa/profiles/profile_menu_controller.mm
@@ -5,6 +5,7 @@
 #import "chrome/browser/ui/cocoa/profiles/profile_menu_controller.h"
 
 #include "base/mac/scoped_nsobject.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/avatar_menu.h"
@@ -25,6 +26,20 @@
 #include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/gfx/image/image.h"
 
+namespace {
+
+// Used in UMA histogram macros, shouldn't be reordered or renumbered
+enum ValidateMenuItemSelector {
+  UNKNOWN_SELECTOR = 0,
+  NEW_PROFILE,
+  EDIT_PROFILE,
+  SWITCH_PROFILE_MENU,
+  SWITCH_PROFILE_DOCK,
+  MAX_VALIDATE_MENU_SELECTOR,
+};
+
+}  // namespace
+
 @interface ProfileMenuController (Private)
 - (void)initializeMenu;
 @end
@@ -169,8 +184,31 @@ class Observer : public chrome::BrowserListObserver,
            [menuItem action] != @selector(editProfile:);
   }
 
-  const AvatarMenu::Item& itemData = avatarMenu_->GetItemAt(
-      avatarMenu_->GetActiveProfileIndex());
+  size_t index = avatarMenu_->GetActiveProfileIndex();
+  if (avatarMenu_->GetNumberOfItems() <= index) {
+    ValidateMenuItemSelector currentSelector = UNKNOWN_SELECTOR;
+    if ([menuItem action] == @selector(newProfile:))
+      currentSelector = NEW_PROFILE;
+    else if ([menuItem action] == @selector(editProfile:))
+      currentSelector = EDIT_PROFILE;
+    else if ([menuItem action] == @selector(switchToProfileFromMenu:))
+      currentSelector = SWITCH_PROFILE_MENU;
+    else if ([menuItem action] == @selector(switchToProfileFromDock:))
+      currentSelector = SWITCH_PROFILE_DOCK;
+    UMA_HISTOGRAM_BOOLEAN("Profile.ValidateMenuItemInvalidIndex.IsGuest",
+                          activeProfile->IsGuestSession());
+    UMA_HISTOGRAM_CUSTOM_COUNTS(
+        "Profile.ValidateMenuItemInvalidIndex.ProfileCount",
+        avatarMenu_->GetNumberOfItems(),
+        1, 20, 20);
+    UMA_HISTOGRAM_ENUMERATION("Profile.ValidateMenuItemInvalidIndex.Selector",
+                              currentSelector,
+                              MAX_VALIDATE_MENU_SELECTOR);
+
+    return NO;
+  }
+
+  const AvatarMenu::Item& itemData = avatarMenu_->GetItemAt(index);
   if ([menuItem action] == @selector(switchToProfileFromDock:) ||
       [menuItem action] == @selector(switchToProfileFromMenu:)) {
     if (!itemData.legacy_supervised)