Move PathExists to base namespace.

base/nix/mime_util_xdg.cc

Index: base/nix/mime_util_xdg.cc
diff --git a/base/nix/mime_util_xdg.cc b/base/nix/mime_util_xdg.cc
index a611e4d1cdd9636772d7cab41b3be23ba6ca9e02..7c1d66049975710684c9483cb4ce9abee4e0a1da 100644
--- a/base/nix/mime_util_xdg.cc
+++ b/base/nix/mime_util_xdg.cc
@@ -171,7 +171,7 @@ IconTheme::IconTheme(const std::string& name)
     if (!file_util::DirectoryExists(theme_path))
       continue;
     FilePath theme_index = theme_path.Append("index.theme");
-    if (!index_theme_loaded_ && file_util::PathExists(theme_index)) {
+    if (!index_theme_loaded_ && PathExists(theme_index)) {
       if (!LoadIndexTheme(theme_index))
         return;
       index_theme_loaded_ = true;
@@ -248,7 +248,7 @@ FilePath IconTheme::GetIconPathUnderSubdir(const std::string& icon_name,
     for (size_t i = 0; i < icon_formats->size(); ++i) {
       icon_path = dir_iter->Append(subdir);
       icon_path = icon_path.Append(icon_name + (*icon_formats)[i]);
-      if (file_util::PathExists(icon_path))
+      if (PathExists(icon_path))
         return icon_path;
     }
   }
@@ -490,7 +490,7 @@ FilePath LookupFallbackIcon(const std::string& icon_name) {
   for (iter = icon_dirs->begin(); iter != icon_dirs->end(); ++iter) {
     for (size_t i = 0; i < icon_formats->size(); ++i) {
       FilePath icon = iter->first.Append(icon_name + (*icon_formats)[i]);
-      if (file_util::PathExists(icon))
+      if (PathExists(icon))
         return icon;
     }
   }
@@ -640,7 +640,7 @@ FilePath GetMimeIcon(const std::string& mime_type, size_t size) {
   for (size_t i = 0; i < icon_names.size(); i++) {
     if (icon_names[i][0] == '/') {
       icon_file = FilePath(icon_names[i]);
-      if (file_util::PathExists(icon_file))
+      if (PathExists(icon_file))
         return icon_file;
     } else {
       icon_file = LookupIconInDefaultTheme(icon_names[i], size);