signin: force web signin flow initiated visits to accounts.google.com to their own process.

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index 0a28d0f0c00f5433041fbf7d1d05e903ae5ff555..432d2c13c2fd39f3ad79fe7e9cf0077e4090d3b7 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -844,6 +844,12 @@ bool ChromeContentRendererClient::ShouldFork(WebFrame* frame,
   if (http_method != "GET")
     return false;
 
+  // If this is the Signin process, fork all navigations originating from the
+  // renderer.  The destination page will then be bucketed back to this Signin
+  // process if it is a Signin url, or to another process if not.

[Charlie Reis, 2013/03/04 19:22:24]

Yeah, I suppose there's no easy way to check whether you're doing a POST to a
valid sign-in URL or not from the renderer process.

Ok, we'll rely on the sign-in page not doing POSTs to untrusted pages until
101395 is fixed.  Can you add something to the comment saying why this check has
to be after the POST check?

[tim (not reviewing), 2013/03/04 23:40:19]

I added a CHECK to my if-block to ensure we never fork on POST without doing
something more careful here.

+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSigninProcess))
+    return true;
+
   // If |url| matches one of the prerendered URLs, stop this navigation and try
   // to swap in the prerendered page on the browser process. If the prerendered
   // page no longer exists by the time the OpenURL IPC is handled, a normal