move is_env_cog to a dedicated helper function in gclient_util module

So that it can be shared with code other than scm.

Bug: 339231299
Change-Id: Iba68cc7ebba78c8933598d073861290bb0157c40
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5529883
Auto-Submit: Yiwei Zhang <yiwzhang@google.com>
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>

gclient.py

@@ -1655,8 +1655,7 @@ class GitDependency(Dependency):
     def _IsCog():
         """Returns true if the env is cog"""
         if GitDependency._is_env_cog is None:
-            GitDependency._is_env_cog = os.getcwd().startswith(
-                '/google/cog/cloud')
+            GitDependency._is_env_cog = gclient_utils.IsEnvCog()
 
         return GitDependency._is_env_cog
 

gclient_utils.py

@@ -1201,6 +1201,11 @@ def RunEditor(content, git, git_editor=None):
         os.remove(filename)
 
 
+def IsEnvCog():
+    """Returns whether the command is running in a Cog environment."""
+    return os.getcwd().startswith('/google/cog/cloud')
+
+
 def UpgradeToHttps(url):
     """Upgrades random urls to https://.