Pull gn binary.

This pulls the Windows and Linux binaries down from Google storage on sync. These aren't hooked up to anything yet, and Mac will come later.

BUG=
R=hinoka@google.com

Review URL: https://codereview.chromium.org/31083008

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 3645abc4b01b9bff020e257d381c0247bb68332b

tools/gn/bin/README.txt

diff --git a/tools/gn/bin/README.txt b/tools/gn/bin/README.txt
new file mode 100644
index 0000000..99a7ef3
--- /dev/null
+++ b/tools/gn/bin/README.txt
@@ -0,0 +1,26 @@
+This folder contains GN binaries. They should be automatically downloaded from
+Google Storage by gclient runhooks for the current platform.
+
+
+To upload a file:
+  python ~/depot_tools/upload_to_google_storage.py -b chromium-gn <FILENAME>
+
+To download a file given a .sha1 file:
+  python ~/depot_tools/download_from_google_storage.py -b chromium-gn -s <FILENAME>.sha1
+
+List the contents of GN's Google Storage bucket:
+  python ~/depot_tools/third_party/gsutil/gsutil ls gs://chromium-gn/
+
+To initialize gsutil's credentials:
+  python ~/depot_tools/third_party/gsutil/gsutil config
+
+  That will give a URL which you should log into with your web browser. The
+  username should be the one that is on the ACL for the "chromium-gn" bucket
+  (probably your @google.com address). Contact the build team for help getting
+  access if necessary.
+
+  Copy the code back to the command line util. Ignore the project ID (it's OK
+  to just leave blank when prompted).
+
+gsutil documentation:
+  https://developers.google.com/storage/docs/gsutil

tools/gn/bin/linux/gn.sha1

diff --git a/tools/gn/bin/linux/gn.sha1 b/tools/gn/bin/linux/gn.sha1
new file mode 100644
index 0000000..af60316
--- /dev/null
+++ b/tools/gn/bin/linux/gn.sha1
@@ -0,0 +1 @@
+9c71ff30a0781745029d018313783cc814a8c305
\ No newline at end of file

tools/gn/bin/win/gn.exe.sha1

diff --git a/tools/gn/bin/win/gn.exe.sha1 b/tools/gn/bin/win/gn.exe.sha1
new file mode 100644
index 0000000..492ffbc
--- /dev/null
+++ b/tools/gn/bin/win/gn.exe.sha1
@@ -0,0 +1 @@
+afd819eef0c7a347b4021ac47b722e04e9ff3193
\ No newline at end of file