Allow to have a transparent UA dependent background.

chrome/browser/ui/views/frame/contents_web_view.cc

Index: chrome/browser/ui/views/frame/contents_web_view.cc
diff --git a/chrome/browser/ui/views/frame/contents_web_view.cc b/chrome/browser/ui/views/frame/contents_web_view.cc
index f77f34515dd190739e49d64309bea88f202821c0..771bebaf542059d4c8ebaf3ffa7969733706a737 100644
--- a/chrome/browser/ui/views/frame/contents_web_view.cc
+++ b/chrome/browser/ui/views/frame/contents_web_view.cc
@@ -57,8 +57,10 @@ void ContentsWebView::OnThemeChanged() {
   // view is sized specially for fullscreen tab capture.  See WebView header
   // file comments for more details.
   const int kBackgroundBrightness = 0x33;  // 20%
+  // FIXME: Clear alpha only upon a call to
+  // content::RenderWidgetHostView->SetBackgroundColor(SK_ColorTRANSPARENT).
   const SkColor ntp_background =
-      theme->GetColor(ThemeProperties::COLOR_NTP_BACKGROUND);
+      theme->GetColor(ThemeProperties::COLOR_NTP_BACKGROUND) & 0x00FFFFFF;

[trchen, 2016/02/25 02:30:12]

ditto.

[Julien Isorce Samsung, 2016/02/25 11:33:55]

Same

   set_background(views::Background::CreateSolidBackground(
       SkColorGetR(ntp_background) * kBackgroundBrightness / 0xFF,
       SkColorGetG(ntp_background) * kBackgroundBrightness / 0xFF,