Modified the pepper file chooser API to support filtering files by extensions.

chrome/browser/ui/gtk/select_file_dialog_impl_gtk.cc

Index: chrome/browser/ui/gtk/select_file_dialog_impl_gtk.cc
diff --git a/chrome/browser/ui/gtk/select_file_dialog_impl_gtk.cc b/chrome/browser/ui/gtk/select_file_dialog_impl_gtk.cc
index 3544eb3170c3954f3a45505bb9937e8f3dee91d0..b657f7f68620a0240fa6ccd966713ac838a2f989 100644
--- a/chrome/browser/ui/gtk/select_file_dialog_impl_gtk.cc
+++ b/chrome/browser/ui/gtk/select_file_dialog_impl_gtk.cc
@@ -19,7 +19,6 @@
 #include "chrome/browser/ui/select_file_dialog.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/generated_resources.h"
-#include "net/base/mime_util.h"
 #include "ui/base/gtk/gtk_signal.h"
 #include "ui/base/l10n/l10n_util.h"
 
@@ -228,27 +227,11 @@ void SelectFileDialogImplGTK::AddFilters(GtkFileChooser* chooser) {
     for (size_t j = 0; j < file_types_.extensions[i].size(); ++j) {
       const std::string& current_extension = file_types_.extensions[i][j];
       if (!current_extension.empty()) {
-        std::string mime_type;
-        bool found_valid_mime_type;
-        {
-          // Allow IO in the file dialog. (http://crbug.com/72637)
-          base::ThreadRestrictions::ScopedAllowIO allow_io;
-          found_valid_mime_type = net::GetMimeTypeFromExtension(
-            current_extension, &mime_type);
-        }
         if (!filter)
           filter = gtk_file_filter_new();
-
-        // Try to add a mime-type filter instead of an extension filter if
-        // possible. (http://crbug.com/12347)
-        if (found_valid_mime_type) {
-          gtk_file_filter_add_mime_type(filter, mime_type.c_str());
-          fallback_labels.insert(mime_type);
-        } else {
-          std::string pattern = "*." + current_extension;
-          gtk_file_filter_add_pattern(filter, pattern.c_str());
-          fallback_labels.insert(pattern);
-        }
+        std::string pattern = "*." + current_extension;
+        gtk_file_filter_add_pattern(filter, pattern.c_str());
+        fallback_labels.insert(pattern);
       }
     }
     // We didn't find any non-empty extensions to filter on.
@@ -262,7 +245,7 @@ void SelectFileDialogImplGTK::AddFilters(GtkFileChooser* chooser) {
           file_types_.extension_description_overrides[i]).c_str());
     } else {
       // There is no system default filter description so we use
-      // the MIME types themselves if the description is blank.
+      // the extensions themselves if the description is blank.
       std::vector<std::string> fallback_labels_vector(fallback_labels.begin(),
                                                       fallback_labels.end());
       std::string fallback_label = JoinString(fallback_labels_vector, ',');