Support painting panels with chromium themes on GTK.

chrome/browser/ui/gtk/browser_window_gtk.cc

Index: chrome/browser/ui/gtk/browser_window_gtk.cc
diff --git a/chrome/browser/ui/gtk/browser_window_gtk.cc b/chrome/browser/ui/gtk/browser_window_gtk.cc
index c30674c868c2acf0b20a20f225959c9be4dc9dde..7d3136b0b76eb19e737631857227743a22d5199e 100644
--- a/chrome/browser/ui/gtk/browser_window_gtk.cc
+++ b/chrome/browser/ui/gtk/browser_window_gtk.cc
@@ -909,7 +909,7 @@ void BrowserWindowGtk::Restore() {
     gtk_window_deiconify(window_);
 }
 
-bool BrowserWindowGtk::ShouldDrawContentDropShadow() {
+bool BrowserWindowGtk::ShouldDrawContentDropShadow() const {
   return !IsMaximized() && UseCustomFrame();
 }
 
@@ -2451,8 +2451,7 @@ bool BrowserWindowGtk::IsBookmarkBarSupported() const {
 bool BrowserWindowGtk::UsingCustomPopupFrame() const {
   ThemeServiceGtk* theme_provider = ThemeServiceGtk::GetFrom(
       browser()->profile());
-  return !theme_provider->UsingNativeTheme() &&
-         (browser()->is_type_popup() || browser()->is_type_panel());
+  return !theme_provider->UsingNativeTheme() && browser()->is_type_popup();
 }
 
 BrowserTitlebar* BrowserWindowGtk::CreateBrowserTitlebar() {
@@ -2516,7 +2515,7 @@ bool BrowserWindowGtk::GetWindowEdge(int x, int y, GdkWindowEdge* edge) {
   return false;
 }
 
-bool BrowserWindowGtk::UseCustomFrame() {
+bool BrowserWindowGtk::UseCustomFrame() const {
   // We don't use the custom frame for app mode windows or app window popups.
   return use_custom_frame_pref_.GetValue() && !browser_->is_app();
 }
@@ -2558,12 +2557,6 @@ void BrowserWindowGtk::PlaceBookmarkBar(bool is_floating) {
   }
 }
 
-BrowserWindowGtk::TitleDecoration BrowserWindowGtk::GetWindowTitle(
-    std::string* title) const {
-  *title = UTF16ToUTF8(browser()->GetWindowTitleForCurrentTab());
-  return PLAIN_TEXT;
-}
-
 // static
 bool BrowserWindowGtk::GetCustomFramePrefDefault() {
   // Ideally, we'd use the custom frame by default and just fall back on using