Grant access to files in PageState, which have already been validated.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 54dc97c9334af383e26865ace77ef634aa1482b6..508264555c9c22473e69025861f07a82b8b41994 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -1456,14 +1456,24 @@ bool RenderViewHostImpl::CanAccessFilesOfPageState(
       ChildProcessSecurityPolicyImpl::GetInstance();
 
   const std::vector<base::FilePath>& file_paths = state.GetReferencedFiles();
-  for (std::vector<base::FilePath>::const_iterator file = file_paths.begin();
-       file != file_paths.end(); ++file) {
-    if (!policy->CanReadFile(GetProcess()->GetID(), *file))
+  for (const auto& file : file_paths) {
+    if (!policy->CanReadFile(GetProcess()->GetID(), file))
       return false;
   }
   return true;
 }
 
+void RenderViewHostImpl::GrantFileAccessFromPageState(const PageState& state) {
+  ChildProcessSecurityPolicyImpl* policy =
+      ChildProcessSecurityPolicyImpl::GetInstance();
+
+  const std::vector<base::FilePath>& file_paths = state.GetReferencedFiles();
+  for (const auto& file : file_paths) {
+    if (!policy->CanReadFile(GetProcess()->GetID(), file))
+      policy->GrantReadFile(GetProcess()->GetID(), file);
+  }
+}
+
 void RenderViewHostImpl::AttachToFrameTree() {
   FrameTree* frame_tree = delegate_->GetFrameTree();