fix external protocol handling for OOPIFs

chrome/browser/ui/cocoa/external_protocol_dialog.mm

Index: chrome/browser/ui/cocoa/external_protocol_dialog.mm
diff --git a/chrome/browser/ui/cocoa/external_protocol_dialog.mm b/chrome/browser/ui/cocoa/external_protocol_dialog.mm
index 48d087f3ded85dfaee9face0654d30e7bf54d73d..37336d2b324d3210750c88f531ed02097f0f3075 100644
--- a/chrome/browser/ui/cocoa/external_protocol_dialog.mm
+++ b/chrome/browser/ui/cocoa/external_protocol_dialog.mm
@@ -8,9 +8,11 @@
 #include "base/metrics/histogram_macros.h"
 #include "chrome/browser/external_protocol/external_protocol_handler.h"
 #include "chrome/browser/shell_integration.h"
+#include "chrome/browser/tab_contents/tab_util.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/strings/grit/components_strings.h"
+#include "content/public/browser/web_contents.h"

[msw, 2016/12/19 20:26:55]

optional nit: remove this include, it's not explicitly needed (type fwd declared
by tab_util.h and not dereferenced here)

[davidsac (gone - try alexmos), 2016/12/19 22:23:45]

Done.

 #include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/gfx/text_elider.h"
 
@@ -115,8 +117,10 @@ void ExternalProtocolHandler::RunExternalProtocolDialog(
     UMA_HISTOGRAM_LONG_TIMES("clickjacking.launch_url",
                              base::Time::Now() - creation_time_);
 
-    ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck(
-        url_, render_process_host_id_, routing_id_);
+    content::WebContents* web_contents =
+        tab_util::GetWebContentsByID(render_process_host_id_, routing_id_);

[sky, 2016/12/15 20:44:28]

How do you know this returns non-null by the time you get here?

[davidsac (gone - try alexmos), 2016/12/15 22:40:23]

We don't.  The first action in
ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck is to make sure that the
web_contents is not null, and return if it is.  Does this seem like it would
work?  Or do you think it's better to do the null checks at its call sites?

[msw, 2016/12/19 20:26:55]

I can't claim to speak for Scott, but that seems okay to me.

[davidsac (gone - try alexmos), 2016/12/19 22:23:45]

Acknowledged.

+
+    ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck(url_, web_contents);
   }
 
   [self autorelease];