deps: add fetch_cmake variable

Required for CQ to build with CMake.

Bug: dawn:2435
Change-Id: Id4dc357466b55cb01b9e685d39e8c09c83f9d70a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/177182
Reviewed-by: Austin Eng <enga@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
diff --git a/DEPS b/DEPS
index 8c27fa2..a3ed7ba 100644
--- a/DEPS
+++ b/DEPS
@@ -57,7 +57,9 @@
 
   # 'magic' text to tell depot_tools that git submodules should be accepted
   # but parity with DEPS file is expected.
-  'SUBMODULE_MIGRATION': 'True'
+  'SUBMODULE_MIGRATION': 'True',
+
+  'fetch_cmake': False
 }
 
 deps = {
@@ -248,7 +250,7 @@
   },
 
   'tools/cmake': {
-    'condition': 'dawn_node and (host_os == "mac" or host_os == "linux")',
+    'condition': '(fetch_cmake or dawn_node) and (host_os == "mac" or host_os == "linux")',
     'packages': [{
       'package': 'infra/3pp/tools/cmake/${{platform}}',
       'version': Var('dawn_cmake_version'),
@@ -476,7 +478,7 @@
   {
     'name': 'cmake_win32',
     'pattern': '.',
-    'condition': 'dawn_node and host_os == "win"',
+    'condition': '(fetch_cmake or dawn_node) and host_os == "win"',
     'action': [ 'python3',
                 'third_party/depot_tools/download_from_google_storage.py',
                 '--no_resume',
@@ -490,7 +492,7 @@
   {
     'name': 'cmake_win32_extract',
     'pattern': '.',
-    'condition': 'dawn_node and host_os == "win"',
+    'condition': '(fetch_cmake or dawn_node) and host_os == "win"',
     'action': [ 'python3',
                 'scripts/extract.py',
                 'tools/cmake-win32.zip',