Add fast --HEAD option to upstream-diff.

man/man1/git-upstream-diff.1

Index: man/man1/git-upstream-diff.1
diff --git a/man/man1/git-upstream-diff.1 b/man/man1/git-upstream-diff.1
index fbe57af2555667b1658dfce7ec0babe2e679167e..f25800ff00555d7a176b732ed365c4ea1664d144 100644
--- a/man/man1/git-upstream-diff.1
+++ b/man/man1/git-upstream-diff.1
@@ -2,12 +2,12 @@
 .\"     Title: git-upstream-diff
 .\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
 .\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
-.\"      Date: 04/10/2014
+.\"      Date: 05/07/2014
 .\"    Manual: Chromium depot_tools Manual
-.\"    Source: depot_tools 68b1017
+.\"    Source: depot_tools cab11c5
 .\"  Language: English
 .\"
-.TH "GIT\-UPSTREAM\-DIFF" "1" "04/10/2014" "depot_tools 68b1017" "Chromium depot_tools Manual"
+.TH "GIT\-UPSTREAM\-DIFF" "1" "05/07/2014" "depot_tools cab11c5" "Chromium depot_tools Manual"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -81,6 +81,14 @@ This is particularly useful to show
 files have been changed in comparison to the upstream branch\&.
 .RE
 .PP
+\-\-staged
+.RS 4
+Diff against the staged (cached) changes, instead of against the working directory\&. This is
+\fIsubstantially\fR
+faster on large repos, but doesn\(cqt take into account unstaged changes (i\&.e\&. changes in your working copy which you haven\(cqt staged with
+git add)\&.
+.RE
+.PP
 \-\- <filename patterns>*
 .RS 4
 Restrict the diff to only show the diff for given files compared to the upstream\&.