Refactoring: Use fake cwd in release script tests.

tools/push-to-trunk/chromium_roll.py

Index: tools/push-to-trunk/chromium_roll.py
diff --git a/tools/push-to-trunk/chromium_roll.py b/tools/push-to-trunk/chromium_roll.py
index c09d9398429f1d45451e14167546f39284e0eb02..35603a21fac40b46e65fb25e70f28f83494a4332 100755
--- a/tools/push-to-trunk/chromium_roll.py
+++ b/tools/push-to-trunk/chromium_roll.py
@@ -13,7 +13,6 @@ CHROMIUM = "CHROMIUM"
 
 CONFIG = {
   PERSISTFILE_BASENAME: "/tmp/v8-chromium-roll-tempfile",
-  DOT_GIT_LOCATION: ".git",
 }
 
 
@@ -43,7 +42,7 @@ class SwitchChromium(Step):
     self["v8_path"] = os.getcwd()
     cwd = self._options.chromium
     os.chdir(cwd)
-    self.InitialEnvironmentChecks()
+    self.InitialEnvironmentChecks(cwd)
     # Check for a clean workdir.
     if not self.GitIsWorkdirClean(cwd=cwd):  # pragma: no cover
       self.Die("Workspace is not clean. Please commit or undo your changes.")