permissionrequest API for guest Download.

content/public/browser/web_contents_delegate.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_DELEGATE_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_DELEGATE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 205 matching lines @@
   // Invoked when the page loses mouse capture.
   virtual void LostCapture() {}
 
   // Notification that |contents| has gained focus.
   virtual void WebContentsFocused(WebContents* contents) {}
 
   // Asks the delegate if the given tab can download.
   virtual bool CanDownload(RenderViewHost* render_view_host,
                            int request_id,
                            const std::string& request_method);
+  virtual void CanDownloadAsync(RenderViewHost* render_view_host,

[asanka, 2013/03/25 18:15:11]

Why are you adding another callback instead of making CanDownload async? 

With this CL, CanDownloadAsync() is only called when
WebContents::GetRenderProcessHost()->IsGuest() is true. And CanDownload() is
only called when that condition is false.

[lazyboy, 2013/03/25 18:36:40]

I was worried of slowing down !IsGuest() case (which should be by far the most
common case) by making them async.
Is it acceptable to make CanDownload async for all cases?
Ty.

[asanka, 2013/03/25 18:58:11]

Yes. The delegate can always invoke the callback synchronously if it can respond
immediately.

Part of the problem is that the distinction between the two callbacks is not
clear at all from the content/ API. On the surface it looks like it's sync vs.
async. But in reality it's based on whether or not the render process host is
associated with a guest renderer.

Having a single API is simpler. Please indicate here that it's permissible to
invoke the callback synchronously.

[lazyboy, 2013/03/25 20:13:05]

Changed back to single CanDownload() function.
Done.

+                                int request_id,
+                                const std::string& request_method,
+                                const base::Callback<void(bool)>& callback);
 
   // Return much extra vertical space should be allotted to the
   // render view widget during various animations (e.g. infobar closing).
   // This is used to make painting look smoother.
   virtual int GetExtraRenderViewHeight() const;
 
   // Returns true if the context menu operation was handled by the delegate.
   virtual bool HandleContextMenu(const content::ContextMenuParams& params);
 
   // Opens source view for given WebContents that is navigated to the given
@@ skipping 192 matching lines @@
   // Called when |this| is no longer the WebContentsDelegate for |source|.
   void Detach(WebContents* source);
 
   // The WebContents that this is currently a delegate for.
   std::set<WebContents*> attached_contents_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_DELEGATE_H_