Fix views examples crash by returning appropriate colors from GetSystemColor().

Fix views examples crash by returning appropriate colors from GetSystemColor().

This fixes the following crash:
[0203/175206:FATAL:native_theme_gtk.cc(43)] Check failed: false. Invalid color_id: 4
Backtrace:
        base::debug::StackTrace::StackTrace() [0x7f87a16293c6]
        logging::LogMessage::~LogMessage() [0x7f87a1656032]
        gfx::NativeThemeGtk::GetSystemColor() [0x7f87a1cb7c32]
        views::TextButtonBase::TextButtonBase() [0x7f87a1ea1090]
        views::TextButton::TextButton() [0x7f87a1ea25ec]
        views::examples::TreeViewExample::CreateExampleView() [0x44253b]
        views::examples::(anonymous namespace)::ContainerView::ViewHierarchyChanged() [0x449f6a]
        views::View::ViewHierarchyChangedImpl() [0x7f87a1f13027]
        views::View::PropagateAddNotifications() [0x7f87a1f12e75]
        views::View::PropagateAddNotifications() [0x7f87a1f12e40]
        views::View::AddChildViewAt() [0x7f87a1f0d375]
        views::View::AddChildView() [0x7f87a1f0d09f]
        views::GridLayout::AddViewState() [0x7f87a1f04589]
        views::GridLayout::AddView() [0x7f87a1f0335b]
        views::GridLayout::AddView() [0x7f87a1f03146]
        views::GridLayout::AddView() [0x7f87a1f030e9]
        views::GridLayout::AddView() [0x7f87a1f02fa2]
        views::examples::ExamplesWindowContents::InitExamplesWindow() [0x4370de]
        views::examples::ExamplesWindowContents::ViewHierarchyChanged() [0x436cc1]
        views::View::ViewHierarchyChangedImpl() [0x7f87a1f13027]
        views::View::PropagateAddNotifications() [0x7f87a1f12e75]
        views::View::AddChildViewAt() [0x7f87a1f0d375]
        views::ClientView::ViewHierarchyChanged() [0x7f87a1f327e4]
        views::View::ViewHierarchyChangedImpl() [0x7f87a1f13027]
        views::View::PropagateAddNotifications() [0x7f87a1f12e75]
        views::View::AddChildViewAt() [0x7f87a1f0d375]
        views::NonClientView::ViewHierarchyChanged() [0x7f87a1f38de4]
        views::View::ViewHierarchyChangedImpl() [0x7f87a1f13027]
        views::View::PropagateAddNotifications() [0x7f87a1f12e75]
        views::View::AddChildViewAt() [0x7f87a1f0d375]
        views::View::AddChildView() [0x7f87a1f0d09f]
        views::internal::RootView::SetContentsView() [0x7f87a1f1cce4]
        views::Widget::SetContentsView() [0x7f87a1f2b522]
        views::Widget::Init() [0x7f87a1f2b187]
        views::Widget::CreateWindowWithParentAndBounds() [0x7f87a1f2ad0a]
        views::Widget::CreateWindowWithBounds() [0x7f87a1f2ac93]
        views::examples::ShowExamplesWindow() [0x43652b]
        main [0x412388]
        0x7f879cb6aeff
        0x412099

Trace/breakpoint trap

R=sky@chromium.org

Review URL: https://chromiumcodereview.appspot.com/9307091

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@120468 0039d316-1c4b-4281-b951-d872f2087c98