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

chrome/browser/download/download_item.cc

Index: chrome/browser/download/download_item.cc
diff --git a/chrome/browser/download/download_item.cc b/chrome/browser/download/download_item.cc
index 52948f8e5c17113f37bb9b1c9d4a0cd8384f7634..88ed28c2bb91e636dff5c9fd9749b6ded312f3bf 100644
--- a/chrome/browser/download/download_item.cc
+++ b/chrome/browser/download/download_item.cc
@@ -132,6 +132,7 @@ DownloadItem::DownloadItem(DownloadManager* download_manager,
       download_manager_(download_manager),
       is_paused_(false),
       open_when_complete_(false),
+      file_exists_(true),
       safety_state_(SAFE),
       danger_type_(NOT_DANGEROUS),
       auto_opened_(false),
@@ -172,6 +173,7 @@ DownloadItem::DownloadItem(DownloadManager* download_manager,
       download_manager_(download_manager),
       is_paused_(false),
       open_when_complete_(false),
+      file_exists_(true),
       safety_state_(GetSafetyState(info.is_dangerous_file,
                                    info.is_dangerous_url)),
       danger_type_(GetDangerType(info.is_dangerous_file,
@@ -211,6 +213,7 @@ DownloadItem::DownloadItem(DownloadManager* download_manager,
       download_manager_(download_manager),
       is_paused_(false),
       open_when_complete_(false),
+      file_exists_(true),
       safety_state_(SAFE),
       danger_type_(NOT_DANGEROUS),
       auto_opened_(false),
@@ -362,6 +365,11 @@ void DownloadItem::OnAllDataSaved(int64 size) {
   StopProgressTimer();
 }
 
+void DownloadItem::OnDownloadedFileRemoved() {
+  file_exists_ = false;
+  UpdateObservers();
+}
+
 void DownloadItem::Completed() {
   VLOG(20) << " " << __FUNCTION__ << "() "
            << DebugString(false);