AU: Update status to DOWNLOADING only after receiving some bytes from server.

download_action.cc

Index: download_action.cc
diff --git a/download_action.cc b/download_action.cc
index 5ecb99e435e66f23fef780fe2660fb64121c58d7..5096703419fe06ce56da445fdd2307b6fade614c 100644
--- a/download_action.cc
+++ b/download_action.cc
@@ -74,6 +74,9 @@ void DownloadAction::PerformAction() {
       return;
     }
   }
+  if (delegate_) {
+    delegate_->SetDownloadStatus(true);  // Set to active.
+  }
   http_fetcher_->BeginTransfer(install_plan_.download_url);
 }
 
@@ -82,6 +85,9 @@ void DownloadAction::TerminateProcessing() {
   CHECK_EQ(writer_->Close(), 0);
   writer_ = NULL;
   http_fetcher_->TerminateTransfer();
+  if (delegate_) {
+    delegate_->SetDownloadStatus(false);  // Set to inactive.
+  }
 }
 
 void DownloadAction::ReceivedBytes(HttpFetcher *fetcher,
@@ -116,6 +122,9 @@ void DownloadAction::TransferComplete(HttpFetcher *fetcher, bool successful) {
     CHECK_EQ(writer_->Close(), 0) << errno;
     writer_ = NULL;
   }
+  if (delegate_) {
+    delegate_->SetDownloadStatus(false);  // Set to inactive.
+  }
   ActionExitCode code =
       successful ? kActionCodeSuccess : kActionCodeDownloadTransferError;
   if (code == kActionCodeSuccess) {