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

chrome/browser/signin/signin_manager.h

Index: chrome/browser/signin/signin_manager.h
diff --git a/chrome/browser/signin/signin_manager.h b/chrome/browser/signin/signin_manager.h
index 2272c7acc0d17dc479fdf403ea2052941bd8b484..434e0ec77b7df7aed35bc711f16f0e2a57ea3f1a 100644
--- a/chrome/browser/signin/signin_manager.h
+++ b/chrome/browser/signin/signin_manager.h
@@ -195,6 +195,14 @@ class SigninManager : public GaiaAuthConsumer,
   // ignored).
   bool IsSignoutProhibited() const;
 
+  // Allows the SigninManager to track the privileged signin process
+  // identified by |process_id| so that we can later ask (via IsSigninProcess)
+  // if it is safe to sign the user in from the current context (see
+  // OneClickSigninHelper).

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

nit: Mention that this resets if the process terminates.

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

Done.

+  void SetSigninProcess(int process_id);
+  bool IsSigninProcess(int process_id) const;
+  bool HasSigninProcess() const;
+
  protected:
   // Weak pointer to parent profile (protected so FakeSigninManager can access
   // it).
@@ -331,6 +339,9 @@ class SigninManager : public GaiaAuthConsumer,
 
   base::WeakPtrFactory<SigninManager> weak_pointer_factory_;
 
+  // See SetSigninProcess.  Tracks the currently active signin process
+  // by ID, if there is one.
+  int signin_process_id_;
 
 #if defined(ENABLE_CONFIGURATION_POLICY) && !defined(OS_CHROMEOS)
   // CloudPolicyClient reference we keep while determining whether to create