Add a prebuilt CMake for OS X for the bots.

Built from:
45f4d3fa8a2f61cc092ae461aac4cac1bab4ac6706f98274ea7f314dd315c6d0  cmake-3.1.3.tar.gz

We're still waiting on infra before the buildbot master is up, but let's get
this ready for when we do; it should be fairly easy.

BUG=430237

Change-Id: I3a414743d44052e1aa48759fa5f125db4d4913b5
Reviewed-on: https://boringssl-review.googlesource.com/3670
Reviewed-by: Adam Langley <agl@google.com>

util/bot/DEPS

@@ -25,6 +25,17 @@ hooks = [
                 '-s', 'boringssl/util/bot/cmake-linux64.tar.gz.sha1',
     ],
   },
+  {
+    'name': 'cmake_mac',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=darwin',
+                '--no_auth',
+                '--bucket', 'chromium-tools',
+                '-s', 'boringssl/util/bot/cmake-mac.tar.gz.sha1',
+    ],
+  },
   # TODO(davidben): The cycle time on these bots is on the order of seconds, so
   # these scripts do not currently make any attempt to avoid the extraction step
   # when it's not needed.
@@ -37,4 +48,13 @@ hooks = [
                 'boringssl/util/bot/cmake-linux64/',
     ],
   },
+  {
+    'name': 'cmake_mac_extract',
+    'pattern': '.',
+    'action': [ 'python',
+                'boringssl/util/bot/extract.py',
+                'boringssl/util/bot/cmake-mac.tar.gz',
+                'boringssl/util/bot/cmake-mac/',
+    ],
+  },
 ]

util/bot/cmake-mac.tar.gz.sha1

@@ -0,0 +1 @@
+310df6945ae7f8c9da559d22f5794ee8e578a663