Allow tests to access all files on Chrome OS

Chrome OS browser tests uses |ChromeNetworkDelegate::IsAccessAllowed|
but |g_access_to_all_files_enabled| was not hooked in.

This patch moved |g_access_to_all_files_enabled| to
|IsAccessAllowedInternal| to make sure it's always checked.

Bug: 884773
Change-Id: I5183f3250e13af151a987561bdf5f93a6f0200be
Reviewed-on: https://chromium-review.googlesource.com/1235122
Commit-Queue: Chong Zhang <chongz@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592617}

chrome/browser/net/chrome_network_delegate.cc

@@ -78,6 +78,9 @@ bool g_access_to_all_files_enabled = false;
 
 bool IsAccessAllowedInternal(const base::FilePath& path,
                              const base::FilePath& profile_path) {
+  if (g_access_to_all_files_enabled)
+    return true;
+
 #if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
   return true;
 #else
@@ -296,8 +299,6 @@ bool ChromeNetworkDelegate::OnCanAccessFile(
     const net::URLRequest& request,
     const base::FilePath& original_path,
     const base::FilePath& absolute_path) const {
-  if (g_access_to_all_files_enabled)
-    return true;
   return IsAccessAllowed(original_path, absolute_path, profile_path_);
 }