Conservative update button/label/textfield content

ui/views/controls/button/text_button.cc

Index: ui/views/controls/button/text_button.cc
diff --git a/ui/views/controls/button/text_button.cc b/ui/views/controls/button/text_button.cc
index 1a4c4e700cadce959305fb9e01ea9af2caf37e65..961c70d36d227f1ed49051ae7ccfd0e0220be055 100644
--- a/ui/views/controls/button/text_button.cc
+++ b/ui/views/controls/button/text_button.cc
@@ -291,6 +291,8 @@ void TextButtonBase::SetIsDefault(bool is_default) {
 }
 
 void TextButtonBase::SetText(const string16& text) {
+  if (text == text_)
+    return;
   text_ = text;
   SetAccessibleName(text);
   UpdateTextSize();