Change Painter factory functions to unique_ptr

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++) {
-    views::Painter* painter = nullptr;
+    std::unique_ptr<views::Painter> painter = nullptr;

[msw, 2017/01/19 09:46:53]

nit: |= nullptr| no longer needed.

[Evan Stade, 2017/01/19 16:26:29]

Done.

 
     if (border->PaintsButtonState(paintstate[i].focus, paintstate[i].state)) {
       std::string idr = is_blue ? paintstate[i].idr_blue : paintstate[i].idr;
-      painter = new GtkButtonPainter(idr);
+      painter = base::MakeUnique<GtkButtonPainter>(idr);
     }
 
-    gtk_border->SetPainter(paintstate[i].focus, paintstate[i].state, painter);
+    gtk_border->SetPainter(paintstate[i].focus, paintstate[i].state,

[msw, 2017/01/19 09:46:53]

optional nit/q: i wonder if we can just skip SetPainter for null painters and
simplify this block:
  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));
    }
  }

[Evan Stade, 2017/01/19 16:26:29]

I think you're right, done.

+                           std::move(painter));
   }
 
-  return std::move(gtk_border);
+  return gtk_border;
 }
 
 void GtkUi::AddWindowButtonOrderObserver(
     views::WindowButtonOrderObserver* observer) {
   if (!leading_buttons_.empty() || !trailing_buttons_.empty()) {
     observer->OnWindowButtonOrderingChange(leading_buttons_, trailing_buttons_);
   }
 
   observer_list_.AddObserver(observer);
 }
@@ skipping 342 matching lines @@
 
 float GtkUi::GetDeviceScaleFactor() const {
   return device_scale_factor_;
 }
 
 }  // namespace libgtkui
 
 views::LinuxUI* BuildGtkUi() {
   return new libgtkui::GtkUi;
 }