Fix gtk theme regression introduced in 477aca494328f

chrome/browser/ui/libgtkui/gtk_ui.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/libgtkui/gtk_ui.h"
 
 #include <math.h>
 #include <pango/pango.h>
 #include <X11/Xcursor/Xcursor.h>
 
@@ skipping 669 matching lines @@
       {
           "IDR_BUTTON_DISABLED", "IDR_BLUE_BUTTON_DISABLED", true,
           views::Button::STATE_DISABLED,
       },
   };
 
   bool is_blue =
       owning_button->GetClassName() == views::BlueButton::kViewClassName;
 
   for (unsigned i = 0; i < arraysize(paintstate); i++) {
-    if (border->PaintsButtonState(paintstate[i].focus, paintstate[i].state)) {
-      std::string idr = is_blue ? paintstate[i].idr_blue : paintstate[i].idr;
-      gtk_border->SetPainter(paintstate[i].focus, paintstate[i].state,
-                             base::MakeUnique<GtkButtonPainter>(idr));
-    }
+    std::string idr = is_blue ? paintstate[i].idr_blue : paintstate[i].idr;
+    gtk_border->SetPainter(
+        paintstate[i].focus, paintstate[i].state,
+        border->PaintsButtonState(paintstate[i].focus, paintstate[i].state)
+            ? base::MakeUnique<GtkButtonPainter>(idr)
+            : nullptr);
   }
 
   return gtk_border;
 }
 
 void GtkUi::AddWindowButtonOrderObserver(
     views::WindowButtonOrderObserver* observer) {
   if (!leading_buttons_.empty() || !trailing_buttons_.empty()) {
     observer->OnWindowButtonOrderingChange(leading_buttons_, trailing_buttons_);
   }
@@ skipping 345 matching lines @@
 
 float GtkUi::GetDeviceScaleFactor() const {
   return device_scale_factor_;
 }
 
 }  // namespace libgtkui
 
 views::LinuxUI* BuildGtkUi() {
   return new libgtkui::GtkUi;
 }