DownloadManager intereface refactoring to allow cleaner DownloadItem unit tests.

chrome/browser/download/download_prefs.h

Index: chrome/browser/download/download_prefs.h
diff --git a/chrome/browser/download/download_prefs.h b/chrome/browser/download/download_prefs.h
index 848db7a542060462447a042ce25ad9fce133ef47..0f0495ead14c3da7458326c2c36674707820796b 100644
--- a/chrome/browser/download/download_prefs.h
+++ b/chrome/browser/download/download_prefs.h
@@ -14,6 +14,10 @@
 class DownloadManager;
 class PrefService;
 
+namespace content {
+class BrowserContext;
+}
+
 // Stores all download-related preferences.
 class DownloadPrefs {
  public:
@@ -22,8 +26,11 @@ class DownloadPrefs {
 
   static void RegisterUserPrefs(PrefService* prefs);
 
-  // Returns the DownloadPrefs corresponding to the given DownloadManager.
+  // Returns the DownloadPrefs corresponding to the given DownloadManager
+  // or BrowserContext.
   static DownloadPrefs* FromDownloadManager(DownloadManager* download_manager);
+  static DownloadPrefs* FromBrowserContext(
+      content::BrowserContext* browser_context);
 
   FilePath download_path() const { return *download_path_; }
   int save_file_type() const { return *save_file_type_; }