[Smart Lock] Add a private API to show an error bubble anchored to the Smart Lock app window.

chrome/browser/ui/proximity_auth/proximity_auth_error_bubble.h

Index: chrome/browser/ui/proximity_auth/proximity_auth_error_bubble.h
diff --git a/chrome/browser/ui/proximity_auth/proximity_auth_error_bubble.h b/chrome/browser/ui/proximity_auth/proximity_auth_error_bubble.h
new file mode 100644
index 0000000000000000000000000000000000000000..e5239b9da01d4e45635c6a77c554fa8a6ab13312
--- /dev/null
+++ b/chrome/browser/ui/proximity_auth/proximity_auth_error_bubble.h
@@ -0,0 +1,31 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_PROXIMITY_AUTH_PROXIMITY_AUTH_ERROR_BUBBLE_H_
+#define CHROME_BROWSER_UI_PROXIMITY_AUTH_PROXIMITY_AUTH_ERROR_BUBBLE_H_
+
+#include "base/macros.h"
+#include "base/strings/string16.h"
+#include "url/gurl.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace gfx {
+class Range;
+class Rect;
+}
+
+// Shows an error bubble with the given |message|, with an arrow pointing to the
+// |anchor_rect|. If the |link_range| is non-empty, then that range of the
+// |message| is drawn as a link with |link_url| as the target. When the link is
+// clicked, the target URL opens in a new tab off of the given |web_contents|.
+void ShowProximityAuthErrorBubble(const base::string16& message,
+                                  const gfx::Range& link_range,
+                                  const GURL& link_url,
+                                  const gfx::Rect& anchor_rect,
+                                  content::WebContents* web_contents);
+
+#endif  // CHROME_BROWSER_UI_PROXIMITY_AUTH_PROXIMITY_AUTH_ERROR_BUBBLE_H_