Remove RenderWidget::SetBackground, change IPC to pass a bool.

chrome/browser/chromeos/login/webui_login_view.cc

Index: chrome/browser/chromeos/login/webui_login_view.cc
diff --git a/chrome/browser/chromeos/login/webui_login_view.cc b/chrome/browser/chromeos/login/webui_login_view.cc
index 1a731cbca269d226f73054b07f90d9df377d764d..69759509096e7342b09a993775daa11b02bff1fb 100644
--- a/chrome/browser/chromeos/login/webui_login_view.cc
+++ b/chrome/browser/chromeos/login/webui_login_view.cc
@@ -260,13 +260,7 @@ void WebUILoginView::LoadURL(const GURL & url) {
 
   // TODO(nkostylev): Use WebContentsObserver::RenderViewCreated to track
   // when RenderView is created.
-  // Use a background with transparency to trigger transparency in Webkit.
-  SkBitmap background;
-  background.setConfig(SkBitmap::kARGB_8888_Config, 1, 1);
-  background.allocPixels();
-  background.eraseARGB(0x00, 0x00, 0x00, 0x00);
-  content::RenderViewHost* host = GetWebContents()->GetRenderViewHost();
-  host->GetView()->SetBackground(background);
+  GetWebContents()->GetRenderViewHost()->GetView()->SetBackgroundOpaque(false);
 }
 
 content::WebUI* WebUILoginView::GetWebUI() {