Const-ify DownloadStatusUpdaterDelegate methods.

content/browser/download/download_status_updater_delegate.h

Index: content/browser/download/download_status_updater_delegate.h
diff --git a/content/browser/download/download_status_updater_delegate.h b/content/browser/download/download_status_updater_delegate.h
index c80e43251ddf406a4cefc4fd66c8a6d4e48a1b43..b48c3ff3753dc7d79529a48f115d2d42e6141bb1 100644
--- a/content/browser/download/download_status_updater_delegate.h
+++ b/content/browser/download/download_status_updater_delegate.h
@@ -12,16 +12,16 @@ class CONTENT_EXPORT DownloadStatusUpdaterDelegate {
  public:
   // Returns true if the progress is known (i.e. we know the final size
   // of all downloads).
-  virtual bool IsDownloadProgressKnown() = 0;
+  virtual bool IsDownloadProgressKnown() const = 0;
 
   // Returns the number of downloads that are in progress.
-  virtual int64 GetInProgressDownloadCount() = 0;
+  virtual int64 GetInProgressDownloadCount() const = 0;
 
   // Returns the amount of received data, in bytes.
-  virtual int64 GetReceivedDownloadBytes() = 0;
+  virtual int64 GetReceivedDownloadBytes() const = 0;
 
   // Returns the final size of all downloads, in bytes.
-  virtual int64 GetTotalDownloadBytes() = 0;
+  virtual int64 GetTotalDownloadBytes() const = 0;
 
  protected:
   virtual ~DownloadStatusUpdaterDelegate() {}