Make node script's gclient dependency platform-independent.

This is a small step towards making node build on Windows.

Bug: v8:6105

R=machenbach@chromium.org

Change-Id: I8d3a9b1830bb012d846a791fddc8d1d8d830515e
Reviewed-on: https://chromium-review.googlesource.com/980950
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52400}

tools/node/fetch_deps.py

@@ -73,10 +73,11 @@ def FetchDeps(v8_path):
     env = os.environ.copy()
     # gclient needs to have depot_tools in the PATH.
     env["PATH"] = depot_tools + os.pathsep + env["PATH"]
+    gclient = os.path.join(depot_tools, "gclient.py")
     spec = "solutions = %s" % GCLIENT_SOLUTION
-    subprocess.check_call(["gclient", "sync", "--spec", spec],
-                          cwd=os.path.join(v8_path, os.path.pardir),
-                          env=env)
+    subprocess.check_call([sys.executable, gclient, "sync", "--spec", spec],
+                           cwd=os.path.join(v8_path, os.path.pardir),
+                           env=env)
   except:
     raise
   finally:

tools/node/node_common.py

@@ -15,9 +15,8 @@ def EnsureDepotTools(v8_path, fetch_if_not_exist):
   def _Get(v8_path):
     depot_tools = os.path.join(v8_path, "_depot_tools")
     try:
-      gclient_path = os.path.join(depot_tools, "gclient")
-      gclient_check = subprocess.check_output([gclient_path, "--version"])
-      if "gclient.py" in gclient_check:
+      gclient_path = os.path.join(depot_tools, "gclient.py")
+      if os.path.isfile(gclient_path):
         return depot_tools
     except:
       pass