vibrancy.patch

diff --git a/chrome/browser/ui/views/frame/browser_frame_view_mac.mm b/chrome/browser/ui/views/frame/browser_frame_view_mac.mm
index 380a3c51c2ae0..7845dc78b4bb7 100644
--- a/chrome/browser/ui/views/frame/browser_frame_view_mac.mm
+++ b/chrome/browser/ui/views/frame/browser_frame_view_mac.mm
@@ -429,8 +429,19 @@ void BrowserFrameViewMac::OnPaint(gfx::Canvas* canvas) {
     return;
   }
 
+  canvas->DrawColor(SK_ColorTRANSPARENT);
+
   SkColor frame_color = GetFrameColor(BrowserFrameActiveState::kUseCurrent);
-  canvas->DrawColor(frame_color);
+  SkColor transparent_tint = SkColorSetA(frame_color, 38);
+
+  gfx::Rect contents_bounds = GetBrowserView()->contents_container()->bounds();
+  contents_bounds =
+      views::View::ConvertRectToTarget(GetBrowserView(), this, contents_bounds);
+
+  canvas->Save();
+  canvas->ClipRect(contents_bounds, SkClipOp::kDifference);
+  canvas->DrawColor(transparent_tint);
+  canvas->Restore();
 
   auto* theme_service = ThemeServiceFactory::GetForProfile(
       GetBrowserView()->browser()->profile());
diff --git a/chrome/browser/ui/views/frame/browser_widget.cc b/chrome/browser/ui/views/frame/browser_widget.cc
index d825bc7cb5828..064f9dbf8dda3 100644
--- a/chrome/browser/ui/views/frame/browser_widget.cc
+++ b/chrome/browser/ui/views/frame/browser_widget.cc
@@ -157,6 +157,7 @@ void BrowserWidget::InitBrowserWidget() {
       views::Widget::InitParams::CLIENT_OWNS_WIDGET);
   params.name = "BrowserWidget";
   params.delegate = browser_view_;
+  params.opacity = views::Widget::InitParams::WindowOpacity::kTranslucent;
 
   Browser* browser = browser_view_->browser();
   if (browser->is_type_picture_in_picture()) {
diff --git a/chrome/browser/ui/views/frame/themed_background.cc b/chrome/browser/ui/views/frame/themed_background.cc
index f5f3d4e6c1cfa..ed893b91af2aa 100644
--- a/chrome/browser/ui/views/frame/themed_background.cc
+++ b/chrome/browser/ui/views/frame/themed_background.cc
@@ -102,12 +102,7 @@ void ThemedBackground::PaintBackground(gfx::Canvas* canvas,
                                        const views::View* view,
                                        const BrowserView* browser_view,
                                        ThemeChoice theme_choice) {
-  bool painted =
-      PaintThemeCustomImage(canvas, view, browser_view, theme_choice);
-  if (!painted) {
-    canvas->DrawColor(view->GetColorProvider()->GetColor(
-        GetThemeChoiceInfo(theme_choice, view).second));
-  }
+  canvas->DrawColor(SK_ColorTRANSPARENT);
 }
 
 std::optional<SkColor> ThemedBackground::GetBackgroundColor(
diff --git a/chrome/browser/ui/views/side_panel/side_panel.cc b/chrome/browser/ui/views/side_panel/side_panel.cc
index e1cee41274339..9c8d986418391 100644
--- a/chrome/browser/ui/views/side_panel/side_panel.cc
+++ b/chrome/browser/ui/views/side_panel/side_panel.cc
@@ -236,14 +236,7 @@ class ContentParentBackground : public views::Background {
     SkRRect rrect;
     rrect.setRectRadii(gfx::RectToSkRect(view->GetLocalBounds()), sk_radii);
     SkPath path = SkPath::RRect(rrect);
-    canvas->ClipPath(path, /*do_anti_alias=*/true);
-
-    if (type_ == SidePanelEntry::PanelType::kToolbar) {
-      ThemedBackground::PaintBackground(canvas, view, browser_view_);
-    } else {
-      canvas->DrawColor(
-          view->GetColorProvider()->GetColor(kColorSidePanelBackground));
-    }
+    canvas->DrawColor(SK_ColorTRANSPARENT);
   }
 
  private:
diff --git a/components/remote_cocoa/app_shim/native_widget_ns_window_bridge.mm b/components/remote_cocoa/app_shim/native_widget_ns_window_bridge.mm
index b89085a51a169..d87ef5bc43ae2 100644
--- a/components/remote_cocoa/app_shim/native_widget_ns_window_bridge.mm
+++ b/components/remote_cocoa/app_shim/native_widget_ns_window_bridge.mm
@@ -750,6 +750,15 @@ void NativeWidgetNSWindowBridge::CreateContentView(
   [compositor_view setLayer:background_layer];
   [compositor_view setWantsLayer:YES];
   [bridged_view_ addSubview:compositor_view];
+  if (is_translucent_window_) {
+    NSVisualEffectView* vibrancy_view =
+        [[NSVisualEffectView alloc] initWithFrame:[bridged_view_ bounds]];
+    [vibrancy_view setMaterial:NSVisualEffectMaterialUnderWindowBackground];
+    [vibrancy_view setBlendingMode:NSVisualEffectBlendingModeBehindWindow];
+    [vibrancy_view setState:NSVisualEffectStateActive];
+    [vibrancy_view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+    [bridged_view_ addSubview:vibrancy_view];
+  }
 
   [bridged_view_ setWantsLayer:YES];
   if (corner_radius) {