Click to Open PDF: Open PDF once View PDF is clicked.

chrome/browser/guest_view/web_view/chrome_web_view_permission_helper_delegate.cc

Index: chrome/browser/guest_view/web_view/chrome_web_view_permission_helper_delegate.cc
diff --git a/chrome/browser/guest_view/web_view/chrome_web_view_permission_helper_delegate.cc b/chrome/browser/guest_view/web_view/chrome_web_view_permission_helper_delegate.cc
index 7bdcea59c44544c978530c82be68bcd18bd33669..0d7f93d467b0cc44cfef61db12261135951a676a 100644
--- a/chrome/browser/guest_view/web_view/chrome_web_view_permission_helper_delegate.cc
+++ b/chrome/browser/guest_view/web_view/chrome_web_view_permission_helper_delegate.cc
@@ -62,6 +62,7 @@ bool ChromeWebViewPermissionHelperDelegate::OnMessageReceived(
                         OnCouldNotLoadPlugin)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_RemovePluginPlaceholderHost,
                         OnRemovePluginPlaceholderHost)
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_DownloadPDF, OnDownloadPDF)

[Lei Zhang, 2017/07/07 17:45:45]

So what happens if the IPC message isn't handled?

[tommycli, 2017/07/07 18:35:30]

I looked upstream a few callsites and didn't see a crash. However, we thought
that it would be odd if it was never handled... and probably better as an
explicit no-op in guest view.

     IPC_MESSAGE_UNHANDLED(return false)
   IPC_END_MESSAGE_MAP()
 
@@ -113,6 +114,8 @@ void ChromeWebViewPermissionHelperDelegate::OnPermissionResponse(
 
 #endif  // BUILDFLAG(ENABLE_PLUGINS)
 
+void ChromeWebViewPermissionHelperDelegate::OnDownloadPDF(const GURL& url) {}

[Lei Zhang, 2017/07/07 17:45:45]

Can you explain when we would reach here vs PluginObserver?

[tommycli, 2017/07/07 18:35:30]

I think this is for guest view

[Lei Zhang, 2017/07/07 19:13:28]

Yes, that part is obvious. Let me try to ask better questions:

- Can you explain why this doesn't do anything?
- Is there a test or a demo page where execution would reach this point?
- This is specifically in the web_view directory. What about the code in
c/b/guest_view/app_view and code for other GuestView subclasses?

[amberwon, 2017/07/11 18:08:05]

A no-op is appropriate here, since within GuestView, a download should not be
triggered. In GuestView, WebViews are on an isolated process. Some things that
use GuestView include sign in pages.

There is an extension that can be used to test it:
https://chrome.google.com/webstore/detail/browser-sample/edggnmnajhcbhlnpjnog...

As for the subclasses, none of them seem to deal with plugins.

+
 void ChromeWebViewPermissionHelperDelegate::CanDownload(
     const GURL& url,
     const std::string& request_method,