Detect removed files and reflect the state in chrome://downloads and the download shelf

chrome/browser/download/download_item.h

Index: chrome/browser/download/download_item.h
diff --git a/chrome/browser/download/download_item.h b/chrome/browser/download/download_item.h
index 3a6bbd7f649545e25039b9d3762ef3483cd06244..46b58c31fa435a8642e4d627812a175d05eeb556 100644
--- a/chrome/browser/download/download_item.h
+++ b/chrome/browser/download/download_item.h
@@ -157,13 +157,16 @@ class DownloadItem {
   // when resuming a download (assuming the server supports byte ranges).
   void Cancel(bool update_history);
 
-  // Called when all data has been saved.  Only has display effects.
-  void OnAllDataSaved(int64 size);
-
   // Called by external code (SavePackage) using the DownloadItem interface
   // to display progress when the DownloadItem should be considered complete.
   void MarkAsComplete();
 
+  // Called when all data has been saved. Only has display effects.
+  void OnAllDataSaved(int64 size);
+
+  // Called when the downloaded file is removed.
+  void OnDownloadedFileRemoved();
+
   // Download operation had an error.
   // |size| is the amount of data received so far, and |os_error| is the error
   // code that the operation received.
@@ -258,6 +261,7 @@ class DownloadItem {
   bool is_paused() const { return is_paused_; }
   bool open_when_complete() const { return open_when_complete_; }
   void set_open_when_complete(bool open) { open_when_complete_ = open; }
+  bool file_externally_removed() const { return file_externally_removed_; }
   SafetyState safety_state() const { return safety_state_; }
   void set_safety_state(SafetyState safety_state) {
     safety_state_ = safety_state;
@@ -368,6 +372,9 @@ class DownloadItem {
   // A flag for indicating if the download should be opened at completion.
   bool open_when_complete_;
 
+  // A flag for indicating if the downloaded file is externally removed.
+  bool file_externally_removed_;
+
   // Whether the download is considered potentially safe or dangerous
   // (executable files are typically considered dangerous).
   SafetyState safety_state_;