views: Add OnEnabledChanged() method to View class.

views/controls/button/text_button.cc

Index: views/controls/button/text_button.cc
diff --git a/views/controls/button/text_button.cc b/views/controls/button/text_button.cc
index e72deb3b328d881fcfdd6a4b5f44377f3fc95c1a..e23276338ef6bc22f6a4d4fd25101f5cbe3662f5 100644
--- a/views/controls/button/text_button.cc
+++ b/views/controls/button/text_button.cc
@@ -560,14 +560,11 @@ gfx::Size TextButtonBase::GetMinimumSize() {
   return max_text_size_;
 }
 
-void TextButtonBase::SetEnabled(bool enabled) {
-  if (enabled != IsEnabled()) {
-    CustomButton::SetEnabled(enabled);
-  }
+void TextButtonBase::OnEnabledChanged() {
   // We should always call UpdateColor() since the state of the button might be
   // changed by other functions like CustomButton::SetState().
   UpdateColor();
-  SchedulePaint();
+  CustomButton::OnEnabledChanged();
 }
 
 std::string TextButtonBase::GetClassName() const {