Stop generating the [TOC] in the GN reference docs.

As doing so causes Gitiles to crash.

Also, update the docs with the response file change to
'gn refs'.

R=brettw@chromium.org
BUG=468851, https://code.google.com/p/gitiles/issues/detail?id=75

Review URL: https://codereview.chromium.org/1097423002

Cr-Original-Commit-Position: refs/heads/master@{#326176}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 36a275daed9a044694646530ab58694b487bad4e
diff --git a/tools/gn/command_help.cc b/tools/gn/command_help.cc
index fda8269..7679b17 100644
--- a/tools/gn/command_help.cc
+++ b/tools/gn/command_help.cc
@@ -92,7 +92,11 @@
   const base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
   if (cmdline->HasSwitch(switches::kMarkdown)) {
     OutputString("# GN Reference\n\n");
-    OutputString("[TOC]\n\n");
+
+    // TODO: https://code.google.com/p/gitiles/issues/detail?id=75
+    // Gitiles crashes when rendering the table of contents, so we must omit
+    // it until the bug is fixed.
+    // OutputString("[TOC]\n\n");
     OutputString("*This page is automatically generated from* "
                  "`gn help --markdown all`.\n\n");
   } else {
diff --git a/tools/gn/docs/reference.md b/tools/gn/docs/reference.md
index 39550a2..a405a34 100644
--- a/tools/gn/docs/reference.md
+++ b/tools/gn/docs/reference.md
@@ -1,7 +1,5 @@
 # GN Reference
 
-[TOC]
-
 *This page is automatically generated from* `gn help --markdown all`.
 
 ## **--args**: Specifies build arguments overrides.
@@ -565,7 +563,7 @@
 
 
 ```
-## **gn refs <out_dir> (<label_pattern>|<label>|<file>)* [--all]**
+## **gn refs <out_dir> (<label_pattern>|<label>|<file>|@<response_file>)* [--all]**
 ```
         [--all-toolchains] [--as=...] [--testonly=...] [--type=...]
 
@@ -587,6 +585,11 @@
      that does not contain wildcards and does not match a target or a
      config will be treated as a file.
 
+   - Response file: If the input starts with an "@", it will be
+     interpreted as a path to a file containing a list of labels or
+     file names, one per line. This allows us to handle long lists
+     of inputs without worrying about command line limits.
+
 ```
 
 ### **Options**