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..d4029db6500e98c0f47b4e4659453e88d71a61e5 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_OpenPDF, OnOpenPDF)
     IPC_MESSAGE_UNHANDLED(return false)
   IPC_END_MESSAGE_MAP()
 
@@ -113,6 +114,8 @@ void ChromeWebViewPermissionHelperDelegate::OnPermissionResponse(
 
 #endif  // BUILDFLAG(ENABLE_PLUGINS)
 
+void ChromeWebViewPermissionHelperDelegate::OnOpenPDF(const GURL& url) {}

[lfg, 2017/07/13 13:11:12]

Why do we need an empty IPC handler? Can't you just leave the IPC unhandled?

[tommycli, 2017/07/13 16:26:29]

Back in the days when this had an OnOpenAboutPlugins handler, it was also an
explicit empty function.

IMO simply leaving a message unhandled seems odd because then the next
programmer may assume we forgot to handle it. While an explicit empty function
does indicate that the programmers explicitly decided not to handle it. It may
make sense for the body to contain a comment saying "Guest views should never
trigger PDF downloads."

[lfg, 2017/07/17 13:52:03]

That seems reasonable. Please, add a comment explaining that this is
intentionally left blank.

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