Add ability for Widgets to override the DefaultThemeProvider

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 154d107a63b298fbb7f6d0eb764d924ecc1a734b..3ece58d3e64e8219b5c4111b1d2c7a035b6f40f2 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -123,7 +123,8 @@ Widget::InitParams::InitParams()
       desktop_window_tree_host(NULL),
       layer_type(ui::LAYER_TEXTURED),
       context(NULL),
-      force_show_in_taskbar(false) {
+      force_show_in_taskbar(false),
+      theme_provider(nullptr) {
 }
 
 Widget::InitParams::InitParams(Type type)
@@ -146,7 +147,8 @@ Widget::InitParams::InitParams(Type type)
       desktop_window_tree_host(NULL),
       layer_type(ui::LAYER_TEXTURED),
       context(NULL),
-      force_show_in_taskbar(false) {
+      force_show_in_taskbar(false),
+      theme_provider(nullptr) {
 }
 
 Widget::InitParams::~InitParams() {
@@ -159,6 +161,7 @@ Widget::Widget()
     : native_widget_(NULL),
       widget_delegate_(NULL),
       non_client_view_(NULL),
+      theme_provider_(nullptr),
       dragged_view_(NULL),
       ownership_(InitParams::NATIVE_WIDGET_OWNS_WIDGET),
       is_secondary_widget_(true),
@@ -352,7 +355,10 @@ void Widget::Init(const InitParams& in_params) {
   native_widget_ = CreateNativeWidget(params.native_widget, this)->
                    AsNativeWidgetPrivate();
   root_view_.reset(CreateRootView());
-  default_theme_provider_.reset(new ui::DefaultThemeProvider);
+  if (in_params.theme_provider && GetTopLevelWidget() == this)
+    theme_provider_ = in_params.theme_provider;
+  else
+    default_theme_provider_.reset(new ui::DefaultThemeProvider);

[tdanderson, 2015/09/09 17:38:58]

nit: newline after line 361

[sadrul, 2015/09/09 17:56:57]

I was thinking this could be more like:

  theme_provider_ = in_params.theme_provider;
  if (theme_provider_) {
    DCHECK(is_toplevel_);
  } else {
    default_theme_provider_.reset(....);
  }

Because silently ignoring a custom theme_provider would make it difficult to
figure out what's going on when a developer adds one for a non-toplevel widget.

   if (params.type == InitParams::TYPE_MENU) {
     is_mouse_button_pressed_ =
         internal::NativeWidgetPrivate::IsMouseButtonDown();
@@ -744,18 +750,9 @@ bool Widget::IsVisible() const {
 
 ui::ThemeProvider* Widget::GetThemeProvider() const {
   const Widget* root_widget = GetTopLevelWidget();
-  if (root_widget && root_widget != this) {
-    // Attempt to get the theme provider, and fall back to the default theme
-    // provider if not found.
-    ui::ThemeProvider* provider = root_widget->GetThemeProvider();
-    if (provider)
-      return provider;
-
-    provider = root_widget->default_theme_provider_.get();
-    if (provider)
-      return provider;
-  }
-  return default_theme_provider_.get();
+  if (root_widget && root_widget != this)
+    return root_widget->GetThemeProvider();
+  return theme_provider_ ? theme_provider_ : default_theme_provider_.get();
 }
 
 const ui::NativeTheme* Widget::GetNativeTheme() const {