Use blink::WebSandboxFlags directly in content.

Mirroring this class in content isn't necessary, and leads to cases
where the enum definitions in Blink and Chrome don't match.

BUG=none
NOPRESUBMIT=true

Review URL: https://codereview.chromium.org/1159863003

Cr-Commit-Position: refs/heads/master@{#331713}
diff --git a/content/renderer/render_frame_proxy.h b/content/renderer/render_frame_proxy.h
index a5e43141..65ad70fa 100644
--- a/content/renderer/render_frame_proxy.h
+++ b/content/renderer/render_frame_proxy.h
@@ -26,7 +26,6 @@
 class ChildFrameCompositingHelper;
 class RenderFrameImpl;
 class RenderViewImpl;
-enum class SandboxFlags;
 struct FrameReplicationState;
 
 // When a page's frames are rendered by multiple processes, each renderer has a
@@ -143,7 +142,7 @@
   void OnCompositorFrameSwapped(const IPC::Message& message);
   void OnDisownOpener();
   void OnDidStopLoading();
-  void OnDidUpdateSandboxFlags(SandboxFlags flags);
+  void OnDidUpdateSandboxFlags(blink::WebSandboxFlags flags);
   void OnDispatchLoad();
   void OnDidUpdateName(const std::string& name);
   void OnDidUpdateOrigin(const url::Origin& origin);