Remove redundant SetUp() override from TextfieldTest.

BUG=none
R=msw@chromium.org

Review URL: https://codereview.chromium.org/682843003

Cr-Commit-Position: refs/heads/master@{#301577}

ui/views/controls/textfield/textfield_unittest.cc

@@ -159,8 +159,6 @@ class TextfieldTest : public ViewsTestBase, public TextfieldController {
   }
 
   // ::testing::Test:
-  void SetUp() override { ViewsTestBase::SetUp(); }
-
   void TearDown() override {
     if (widget_)
       widget_->Close();