Fix problems with cross-origin redirects.

Source/core/loader/DocumentThreadableLoader.cpp

Index: Source/core/loader/DocumentThreadableLoader.cpp
diff --git a/Source/core/loader/DocumentThreadableLoader.cpp b/Source/core/loader/DocumentThreadableLoader.cpp
index 4271425ee490fdfc47dc872b02301b4205f0fd7f..087548814abd6d2e48572dd7ec60031d84237296 100644
--- a/Source/core/loader/DocumentThreadableLoader.cpp
+++ b/Source/core/loader/DocumentThreadableLoader.cpp
@@ -187,7 +187,8 @@ void DocumentThreadableLoader::redirectReceived(CachedResource* resource, Resour
     }
 
     // When using access control, only simple cross origin requests are allowed to redirect. The new request URL must have a supported
-    // scheme and not contain the userinfo production. In addition, the redirect response must pass the access control check.
+    // scheme and not contain the userinfo production. In addition, the redirect response must pass the access control check if the
+    // original request was not same-origin.
     if (m_options.crossOriginRequestPolicy == UseAccessControl) {
         bool allowRedirect = false;
         if (m_simpleRequest) {
@@ -195,7 +196,7 @@ void DocumentThreadableLoader::redirectReceived(CachedResource* resource, Resour
             allowRedirect = SchemeRegistry::shouldTreatURLSchemeAsCORSEnabled(request.url().protocol())
                             && request.url().user().isEmpty()
                             && request.url().pass().isEmpty()
-                            && passesAccessControlCheck(redirectResponse, m_options.allowCredentials, securityOrigin(), accessControlErrorDescription);
+                            && (m_sameOriginRequest || passesAccessControlCheck(redirectResponse, m_options.allowCredentials, securityOrigin(), accessControlErrorDescription));

[abarth-chromium, 2013/05/09 04:22:06]

Ah, I see.  I was mis-reading the implementation of isAllowedRedirect.

         }
 
         if (allowRedirect) {
@@ -210,6 +211,11 @@ void DocumentThreadableLoader::redirectReceived(CachedResource* resource, Resour
             // Force any subsequent requests to use these checks.
             m_sameOriginRequest = false;
 
+            // Since the request is no longer same-origin, if the user didn't request credentials in
+            // the first place, update our state so we neither request them nor expect they must be allowed.
+            if (m_options.credentialsRequested == ClientDidNotRequestCredentials)
+                m_options.allowCredentials = DoNotAllowStoredCredentials;
+
             // Remove any headers that may have been added by the network layer that cause access control to fail.
             request.clearHTTPContentType();
             request.clearHTTPReferrer();