Grant permission to the base url when loadDataWithBaseURL is called.

content/browser/frame_host/render_frame_host_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/frame_host/render_frame_host_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 2791 matching lines @@
 
 void RenderFrameHostImpl::UpdatePermissionsForNavigation(
     const CommonNavigationParams& common_params,
     const RequestNavigationParams& request_params) {
   // Browser plugin guests are not allowed to navigate outside web-safe schemes,
   // so do not grant them the ability to request additional URLs.
   if (!GetProcess()->IsForGuestsOnly()) {
     ChildProcessSecurityPolicyImpl::GetInstance()->GrantRequestURL(
         GetProcess()->GetID(), common_params.url);
     if (common_params.url.SchemeIs(url::kDataScheme) &&
-        common_params.base_url_for_data_url.SchemeIs(url::kFileScheme)) {
-      // If 'data:' is used, and we have a 'file:' base url, grant access to
-      // local files.
+        !common_params.base_url_for_data_url.is_empty()) {
+      // Need to grant permission to the base url because bse url will be used
+      // as the origin for font requests.

[Charlie Reis, 2016/07/22 18:31:49]

Let's update the comment, because CORS is not just about font requests (and
because the previous file: comment still applies).  Something like:

When there's a base URL specified for the data URL, we also need to grant access
to the base URL.  This allows file: and other unexpected schemes to be accepted
at commit time and during CORS checks (e.g., for font requests).

[hush (inactive), 2016/07/26 02:42:54]

Done.

       ChildProcessSecurityPolicyImpl::GetInstance()->GrantRequestURL(
           GetProcess()->GetID(), common_params.base_url_for_data_url);
     }
   }
 
   // We may be returning to an existing NavigationEntry that had been granted
   // file access.  If this is a different process, we will need to grant the
   // access again.  Abuse is prevented, because the files listed in the page
   // state are validated earlier, when they are received from the renderer (in
   // RenderFrameHostImpl::CanAccessFilesOfPageState).
@@ skipping 133 matching lines @@
   // handler after it's destroyed so it can't run after the RFHI is destroyed.
   web_bluetooth_service_->SetClientConnectionErrorHandler(base::Bind(
       &RenderFrameHostImpl::DeleteWebBluetoothService, base::Unretained(this)));
 }
 
 void RenderFrameHostImpl::DeleteWebBluetoothService() {
   web_bluetooth_service_.reset();
 }
 
 }  // namespace content