[Resumption 9/11] Handle filename determination for resumed downloads.

content/public/browser/download_item.h

Index: content/public/browser/download_item.h
diff --git a/content/public/browser/download_item.h b/content/public/browser/download_item.h
index 2b80d7f710d22df2592799951aa5592d4b5b8892..6c9011007e308591230732608bfe87f18653facc 100644
--- a/content/public/browser/download_item.h
+++ b/content/public/browser/download_item.h
@@ -155,7 +155,11 @@ class CONTENT_EXPORT DownloadItem : public base::SupportsUserData {
   virtual DownloadId GetGlobalId() const = 0;
   virtual DownloadState GetState() const = 0;
 
-  // Only valid if |GetState() == DownloadItem::INTERRUPTED|.
+  // Returns the most recent interrupt reason for this download. Returns
+  // DOWNLOAD_INTERRUPT_REASON_NONE if there is no previous interrupt reason.
+  // Cancelled downloads return DOWNLOAD_INTERRUPT_REASON_USER_CANCELLED. If
+  // the download was resumed, then the return value is the interrupt reason
+  // prior to resumption.
   virtual DownloadInterruptReason GetLastReason() const = 0;
 
   virtual bool IsPaused() const = 0;