Sets the default background color of inline signin and user manager to grey

extensions/browser/guest_view/web_view/web_view_guest.cc

Index: extensions/browser/guest_view/web_view/web_view_guest.cc
diff --git a/extensions/browser/guest_view/web_view/web_view_guest.cc b/extensions/browser/guest_view/web_view/web_view_guest.cc
index eb1bd4eddcc31c93cd784335ea52ee3c75f69002..e0308594a35d34451afded31dfffca9c2890fe17 100644
--- a/extensions/browser/guest_view/web_view/web_view_guest.cc
+++ b/extensions/browser/guest_view/web_view/web_view_guest.cc
@@ -377,8 +377,15 @@ void WebViewGuest::GuestReady() {
   // WebContents::GetRenderWidgetHostView will return the RWHV of an
   // interstitial page if one is showing at this time. We only want opacity
   // to apply to web pages.
-  web_contents()->GetRenderViewHost()->GetView()->
-      SetBackgroundOpaque(guest_opaque_);
+  if (guest_opaque_) {
+    web_contents()
+        ->GetRenderViewHost()
+        ->GetView()
+        ->FillBackgroundWithDefaultColor();
+  } else {
+    web_contents()->GetRenderViewHost()->GetView()->SetBackgroundColor(
+        SK_ColorTRANSPARENT);
+  }
 }
 
 void WebViewGuest::GuestSizeChangedDueToAutoSize(const gfx::Size& old_size,
@@ -1025,7 +1032,15 @@ void WebViewGuest::SetAllowTransparency(bool allow) {
   if (!web_contents()->GetRenderViewHost()->GetView())
     return;
 
-  web_contents()->GetRenderViewHost()->GetView()->SetBackgroundOpaque(!allow);
+  if (guest_opaque_) {
+    web_contents()
+        ->GetRenderViewHost()
+        ->GetView()
+        ->FillBackgroundWithDefaultColor();
+  } else {
+    web_contents()->GetRenderViewHost()->GetView()->SetBackgroundColor(
+        SK_ColorTRANSPARENT);
+  }
 }
 
 bool WebViewGuest::LoadDataWithBaseURL(const std::string& data_url,