Revert of Introduce a type of View background that stays in sync with its host

ui/views/background.cc

Index: ui/views/background.cc
diff --git a/ui/views/background.cc b/ui/views/background.cc
index e036490a0c24950c931077dd106f41cbbad5b055..190a5a62c346e714f9b7c4dad8a8d79321132a0d 100644
--- a/ui/views/background.cc
+++ b/ui/views/background.cc
@@ -6,14 +6,11 @@
 
 #include "base/logging.h"
 #include "base/macros.h"
-#include "base/scoped_observer.h"
 #include "build/build_config.h"
 #include "ui/gfx/canvas.h"
-#include "ui/gfx/color_palette.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/views/painter.h"
 #include "ui/views/view.h"
-#include "ui/views/view_observer.h"
 
 #if defined(OS_WIN)
 #include "skia/ext/skia_utils_win.h"
@@ -37,32 +34,6 @@
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SolidBackground);
-};
-
-// ThemedSolidBackground is a solid background that stays in sync with a view's
-// native theme.
-class ThemedSolidBackground : public SolidBackground, public ViewObserver {
- public:
-  explicit ThemedSolidBackground(View* view, ui::NativeTheme::ColorId color_id)
-      : SolidBackground(gfx::kPlaceholderColor),
-        observer_(this),
-        color_id_(color_id) {
-    observer_.Add(view);
-    OnViewNativeThemeChanged(view);
-  }
-  ~ThemedSolidBackground() override {}
-
-  // ViewObserver:
-  void OnViewNativeThemeChanged(View* view) override {
-    SetNativeControlColor(view->GetNativeTheme()->GetSystemColor(color_id_));
-    view->SchedulePaint();
-  }
-
- private:
-  ScopedObserver<View, ViewObserver> observer_;
-  ui::NativeTheme::ColorId color_id_;
-
-  DISALLOW_COPY_AND_ASSIGN(ThemedSolidBackground);
 };
 
 class BackgroundPainter : public Background {
@@ -102,13 +73,6 @@
 }
 
 // static
-Background* Background::CreateThemedSolidBackground(
-    View* view,
-    ui::NativeTheme::ColorId color_id) {
-  return new ThemedSolidBackground(view, color_id);
-}
-
-// static
 Background* Background::CreateStandardPanelBackground() {
   // TODO(beng): Should be in NativeTheme.
   return CreateSolidBackground(SK_ColorWHITE);