Add a basic tutorial for the tools in depot_tools.

docs/src/git-freeze.txt

Index: docs/src/git-freeze.txt
diff --git a/docs/src/git-freeze.txt b/docs/src/git-freeze.txt
index 1e2e253e1b80429211b98f78a6475ce219490b07..4a53832526fc0b1c50a7bf2b4f20759bee22706a 100644
--- a/docs/src/git-freeze.txt
+++ b/docs/src/git-freeze.txt
@@ -28,50 +28,7 @@ time you ran git freeze (freshly modified files, new files, etc.).
 
 EXAMPLE
 -------
-
-[subs="specialcharacters,quotes,attributes"]
-----
-[white]**$ git status --short**
-[green]##A##  added_file
-[green]##A##{zwsp}[red]##M## added_file_with_unstaged_changes
-[green]##D##  deleted_file
- [red]##M## modified_file
- [red]##D## unstaged_deleted_file
-[red]##??## unadded_file
-[white]**$ git freeze**
-[white]**$ git status --short**
-[white]**$ git log -n 2 --stat**
-[yellow]##commit 182eccae8e385acba21c9ff2713e98ff4b7e17cd##
-Author: Robert Iannucci <iannucci@chromium.org>
-Date:   Thu Mar 13 17:42:37 2014 -0700
-
-    FREEZE.unindexed
-
- added_file_with_unstaged_changes | 3 [green]##\+\+##{zwsp}[red]##-##
- modified_file                    | 4 [green]##\+\+\+##{zwsp}[red]##-##
- unadded_file                     | 3 [green]##\+\+\+##
- unstaged_deleted_file            | 1 [red]##-##
- 4 files changed, 8 insertions(\+), 3 deletions(-)
-
-[yellow]##commit ce07bdc49a61f54e6142b4bba5cc517cf6802bd4##
-Author: Robert Iannucci <iannucci@chromium.org>
-Date:   Thu Mar 13 17:42:37 2014 -0700
-
-    FREEZE.indexed
-
- added_file                       | 3 [green]##\+\+\+##
- added_file_with_unstaged_changes | 1 [green]##\+##
- deleted_file                     | 1 [red]##-##
- 3 files changed, 4 insertions(+), 1 deletion(-)
-[white]**$ git thaw**
-[white]**$ git status --short**
-[green]##A##  added_file
-[green]##A##{zwsp}[red]##M## added_file_with_unstaged_changes
-[green]##D##  deleted_file
- [red]##M## modified_file
- [red]##D## unstaged_deleted_file
-[red]##??## unadded_file
-----
+demo:1[]
 
 SEE ALSO
 --------