Warn when extensions suggest conflicting download filenames

chrome/browser/extensions/extension_warning_set.h

Index: chrome/browser/extensions/extension_warning_set.h
diff --git a/chrome/browser/extensions/extension_warning_set.h b/chrome/browser/extensions/extension_warning_set.h
index c0510f167f09d44744c746ba26627d7d6fa02a01..9e00823f86d81c6d7d0be7353d1ad34066b1b017 100644
--- a/chrome/browser/extensions/extension_warning_set.h
+++ b/chrome/browser/extensions/extension_warning_set.h
@@ -13,6 +13,10 @@
 
 // TODO(battre) Remove the Extension prefix.
 
+namespace base {
+class FilePath;
+}
+
 class ExtensionSet;
 
 namespace extensions {
@@ -37,6 +41,9 @@ class ExtensionWarning {
     // The extension repeatedly flushed WebKit's in-memory cache, which slows
     // down the overall performance.
     kRepeatedCacheFlushes,
+    // The extension failed to determine the filename of a download because
+    // another extension with higher precedence determined a different filename.
+    kDownloadFilenameConflict,
     kMaxWarningType
   };
 
@@ -69,6 +76,11 @@ class ExtensionWarning {
       const std::string& winning_extension_id);
   static ExtensionWarning CreateRepeatedCacheFlushesWarning(
       const std::string& extension_id);
+  static ExtensionWarning CreateDownloadFilenameConflictWarning(
+      const std::string& losing_extension_id,
+      const std::string& winning_extension_id,
+      const base::FilePath& losing_filename,
+      const base::FilePath& winning_filename);
 
   // Returns the specific warning type.
   WarningType warning_type() const { return type_; }