views: Use default theme background color for all controls (see #3671)

Add new CefViewDelegate::OnThemeChanged callback for optionally overriding
default theme colors when the current theme changes.

libcef/browser/alloy/alloy_browser_main.cc

@@ -37,6 +37,7 @@
 #include "chrome/browser/ui/ui_features.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
+#include "components/color/color_mixers.h"
 #include "components/constrained_window/constrained_window_views.h"
 #include "content/public/browser/gpu_data_manager.h"
 #include "content/public/browser/network_service_instance.h"
@@ -246,6 +247,8 @@ void AlloyBrowserMainParts::ToolkitInitialized() {
 
   // On GTK that builds the native theme that, in turn, adds the GTK core color
   // mixer; core mixers should all be added before we add chrome mixers.
+  ui::ColorProviderManager::Get().AppendColorProviderInitializer(
+      base::BindRepeating(color::AddComponentsColorMixers));
   ui::ColorProviderManager::Get().AppendColorProviderInitializer(
       base::BindRepeating(AddChromeColorMixers));
 }

libcef/browser/views/button_impl.h

@@ -85,7 +85,7 @@ CEF_BUTTON_IMPL_T void CEF_BUTTON_IMPL_D::SetInkDropEnabled(bool enabled) {
   if (enabled) {
     views::InkDrop::Get(ParentClass::root_view())
         ->SetBaseColor(color_utils::BlendTowardMaxContrast(
-            ParentClass::root_view()->background()->get_color(), 0x61));
+            ParentClass::GetBackgroundColor(), 0x61));
   }
 }
 

libcef/browser/views/overlay_view_host.cc

@@ -193,8 +193,6 @@ void CefOverlayViewHost::Init(views::View* host_view,
                            : views::Widget::InitParams::Activatable::kNo;
   widget_->Init(std::move(params));
 
-  view_ = widget_->GetContentsView()->AddChildView(std::move(controls_view));
-
   // Make the Widget background transparent. The View might still be opaque.
   if (widget_->GetCompositor()) {
     widget_->GetCompositor()->SetBackgroundColor(SK_ColorTRANSPARENT);
@@ -213,6 +211,11 @@ void CefOverlayViewHost::Init(views::View* host_view,
     }
   }
 
+  // Call AddChildView after the Widget properties have been configured.
+  // Notifications resulting from this call may attempt to access those
+  // properties (OnThemeChanged calling GetHostView, for example).
+  view_ = widget_->GetContentsView()->AddChildView(std::move(controls_view));
+
   // Set the initial bounds after the View has been added to the Widget.
   // Otherwise, preferred size won't calculate correctly.
   gfx::Rect bounds;

libcef/browser/views/view_impl.h

@@ -675,12 +675,15 @@ CEF_VIEW_IMPL_T void CEF_VIEW_IMPL_D::RequestFocus() {
 
 CEF_VIEW_IMPL_T void CEF_VIEW_IMPL_D::SetBackgroundColor(cef_color_t color) {
   CEF_REQUIRE_VALID_RETURN_VOID();
-  content_view()->SetBackground(views::CreateSolidBackground(color));
+  root_view()->SetBackground(views::CreateSolidBackground(color));
 }
 
 CEF_VIEW_IMPL_T cef_color_t CEF_VIEW_IMPL_D::GetBackgroundColor() {
   CEF_REQUIRE_VALID_RETURN(0U);
-  return content_view()->background()->get_color();
+  if (root_view()->background()) {
+    return root_view()->background()->get_color();
+  }
+  return view_util::GetColor(root_view(), ui::kColorPrimaryBackground);
 }
 
 CEF_VIEW_IMPL_T bool CEF_VIEW_IMPL_D::ConvertPointToScreen(CefPoint& point) {

libcef/browser/views/view_util.cc

@@ -8,10 +8,13 @@
 
 #include "libcef/browser/views/view_adapter.h"
 
+#include "ui/color/color_provider.h"
+#include "ui/color/color_provider_manager.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_conversions.h"
+#include "ui/native_theme/native_theme.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/window/non_client_view.h"
@@ -118,9 +121,24 @@ class UserData : public base::SupportsUserData::Data {
   CefView* view_ref_;
 };
 
+// Based on Widget::GetNativeTheme.
+const ui::NativeTheme* GetDefaultNativeTheme() {
+  return ui::NativeTheme::GetInstanceForNativeUi();
+}
+
+// Based on Widget::GetColorProviderKey.
+ui::ColorProviderKey GetDefaultColorProviderKey() {
+  return GetDefaultNativeTheme()->GetColorProviderKey(/*custom_theme=*/nullptr);
+}
+
+// Based on Widget::GetColorProvider.
+ui::ColorProvider* GetDefaultColorProvider() {
+  return ui::ColorProviderManager::Get().GetColorProviderFor(
+      GetDefaultColorProviderKey());
+}
+
 }  // namespace
 
-const SkColor kDefaultBackgroundColor = SkColorSetARGB(255, 255, 255, 255);
 const char kDefaultFontList[] = "Arial, Helvetica, 14px";
 
 void Register(CefRefPtr<CefView> view) {
@@ -323,4 +341,14 @@ bool ConvertPointFromWindow(views::View* view, gfx::Point* point) {
   return true;
 }
 
+SkColor GetColor(views::View* view, ui::ColorId id) {
+  // |color_provider| will be nullptr if |view| has not yet been added to a
+  // Widget.
+  if (auto color_provider = view->GetColorProvider()) {
+    return color_provider->GetColor(id);
+  }
+
+  return GetDefaultColorProvider()->GetColor(id);
+}
+
 }  // namespace view_util

libcef/browser/views/view_util.h

@@ -9,6 +9,7 @@
 #include "include/views/cef_view.h"
 #include "include/views/cef_window.h"
 
+#include "ui/color/color_id.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/view.h"
 
@@ -45,7 +46,6 @@ class CefWindowDelegate;
 namespace view_util {
 
 // Default values.
-extern const SkColor kDefaultBackgroundColor;
 extern const char kDefaultFontList[];
 
 // Called when a CefView is initialized to create the initial association
@@ -165,6 +165,11 @@ views::View* GetHostView(views::Widget* widget);
 float GetNSWindowTitleBarHeight(views::Widget* widget);
 #endif
 
+// Returns the mixer color for |id|. If |view| has been added to a Widget it
+// will use the Widget's ColorProvider, otherwise it will use the default theme
+// ColorProvider. Returns gfx::kPlaceholderColor if |id| cannot be constructed.
+SkColor GetColor(views::View* view, ui::ColorId id);
+
 }  // namespace view_util
 
 #endif  // CEF_LIBCEF_BROWSER_VIEWS_VIEW_UTIL_H_

libcef/browser/views/view_view.h

@@ -44,10 +44,6 @@ CEF_VIEW_VIEW_T class CefViewView : public ViewsViewClass {
   // CefViewImpl registration has completed so it is safe to call complex
   // views::View-derived methods here.
   virtual void Initialize() {
-    // Use our defaults instead of the Views framework defaults.
-    ParentClass::SetBackground(
-        views::CreateSolidBackground(view_util::kDefaultBackgroundColor));
-
     // TODO(crbug.com/1218186): Remove this, if this view is focusable then it
     // needs to add a name so that the screen reader knows what to announce.
     ParentClass::SetProperty(views::kSkipAccessibilityPaintChecks, true);
@@ -80,6 +76,7 @@ CEF_VIEW_VIEW_T class CefViewView : public ViewsViewClass {
   void RemovedFromWidget() override;
   void OnFocus() override;
   void OnBlur() override;
+  void OnThemeChanged() override;
 
   // Return true if this View is expected to have a minimum size (for example,
   // a button where the minimum size is based on the label).
@@ -214,6 +211,35 @@ CEF_VIEW_VIEW_T void CEF_VIEW_VIEW_D::OnBlur() {
   ParentClass::OnBlur();
 }
 
+CEF_VIEW_VIEW_T void CEF_VIEW_VIEW_D::OnThemeChanged() {
+  // Clear the background, if set.
+  if (ParentClass::background()) {
+    ParentClass::SetBackground(nullptr);
+  }
+
+  // Apply default theme colors.
+  ParentClass::OnThemeChanged();
+
+  // Allow the client to override the default colors.
+  if (cef_delegate()) {
+    cef_delegate()->OnThemeChanged(GetCefView());
+  }
+
+  // If the background is still unset, and the containing Widget is not an
+  // overlay (which has transparent background), then set the background based
+  // on the current theme.
+  if (!ParentClass::background()) {
+    const bool is_overlay_hosted =
+        ParentClass::GetWidget() &&
+        view_util::GetHostView(ParentClass::GetWidget()) != nullptr;
+    if (!is_overlay_hosted) {
+      const SkColor color =
+          view_util::GetColor(this, ui::kColorPrimaryBackground);
+      ParentClass::SetBackground(views::CreateSolidBackground(color));
+    }
+  }
+}
+
 CEF_VIEW_VIEW_T void CEF_VIEW_VIEW_D::NotifyChildViewChanged(
     const views::ViewHierarchyChangedDetails& details) {
   if (!cef_delegate()) {