fix: BrowserView background color in webContents (#33546)

* chore: fix BrowserView background color in webContents

* disable screen capture test on linux

* spec: fix platform failure condition

shell/browser/api/electron_api_browser_view.cc

@@ -6,10 +6,13 @@
 
 #include <vector>
 
+#include "content/browser/renderer_host/render_widget_host_view_base.h"  // nogncheck
+#include "content/public/browser/render_widget_host_view.h"
 #include "shell/browser/api/electron_api_web_contents.h"
 #include "shell/browser/browser.h"
 #include "shell/browser/native_browser_view.h"
 #include "shell/browser/ui/drag_util.h"
+#include "shell/browser/web_contents_preferences.h"
 #include "shell/common/color_util.h"
 #include "shell/common/gin_converters/gfx_converter.h"
 #include "shell/common/gin_helper/dictionary.h"
@@ -155,11 +158,25 @@ gfx::Rect BrowserView::GetBounds() {
 }
 
 void BrowserView::SetBackgroundColor(const std::string& color_name) {
-  view_->SetBackgroundColor(ParseHexColor(color_name));
+  SkColor color = ParseHexColor(color_name);
+  view_->SetBackgroundColor(color);
 
   if (web_contents()) {
     auto* wc = web_contents()->web_contents();
-    wc->SetPageBaseBackgroundColor(ParseHexColor(color_name));
+    wc->SetPageBaseBackgroundColor(color);
+
+    auto* const rwhv = wc->GetRenderWidgetHostView();
+    if (rwhv) {
+      rwhv->SetBackgroundColor(color);
+      static_cast<content::RenderWidgetHostViewBase*>(rwhv)
+          ->SetContentBackgroundColor(color);
+    }
+
+    // Ensure new color is stored in webPreferences, otherwise
+    // the color will be reset on the next load via HandleNewRenderFrame.
+    auto* web_preferences = WebContentsPreferences::From(wc);
+    if (web_preferences)
+      web_preferences->SetBackgroundColor(color);
   }
 }
 

shell/browser/api/electron_api_web_contents.cc

@@ -1487,11 +1487,13 @@ void WebContents::HandleNewRenderFrame(
   // Set the background color of RenderWidgetHostView.
   auto* web_preferences = WebContentsPreferences::From(web_contents());
   if (web_preferences) {
+    absl::optional<SkColor> maybe_color = web_preferences->GetBackgroundColor();
+    web_contents()->SetPageBaseBackgroundColor(maybe_color);
+
     bool guest = IsGuest() || type_ == Type::kBrowserView;
-    absl::optional<SkColor> color =
-        guest ? SK_ColorTRANSPARENT : web_preferences->GetBackgroundColor();
-    web_contents()->SetPageBaseBackgroundColor(color);
-    SetBackgroundColor(rwhv, color.value_or(SK_ColorWHITE));
+    SkColor color =
+        maybe_color.value_or(guest ? SK_ColorTRANSPARENT : SK_ColorWHITE);
+    SetBackgroundColor(rwhv, color);
   }
 
   if (!background_throttling_)