Removed GPR_POSIX_FILE, and changed the files that used it
diff --git a/src/core/lib/security/credentials/google_default/credentials_posix.c b/src/core/lib/security/credentials/google_default/credentials_generic.c
similarity index 81%
rename from src/core/lib/security/credentials/google_default/credentials_posix.c
rename to src/core/lib/security/credentials/google_default/credentials_generic.c
index 42c9d7f..02a6e9e 100644
--- a/src/core/lib/security/credentials/google_default/credentials_posix.c
+++ b/src/core/lib/security/credentials/google_default/credentials_generic.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,12 +31,10 @@
  *
  */
 
-#include <grpc/support/port_platform.h>
-
-#ifdef GPR_POSIX_FILE
-
 #include "src/core/lib/security/credentials/google_default/google_default_credentials.h"
 
+#ifdef GRPC_GOOGLE_CREDENTIALS_GENERIC
+
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
@@ -46,16 +44,16 @@
 
 char *grpc_get_well_known_google_credentials_file_path_impl(void) {
   char *result = NULL;
-  char *home = gpr_getenv("HOME");
-  if (home == NULL) {
-    gpr_log(GPR_ERROR, "Could not get HOME environment variable.");
+  char *base = gpr_getenv(GRPC_GOOGLE_CREDENTIALS_PATH_ENV_VAR);
+  if (base == NULL) {
+    gpr_log(GPR_ERROR, "Could not get " GRPC_GOOGLE_CREDENTIALS_ENV_VAR
+            " environment variable.");
     return NULL;
   }
-  gpr_asprintf(&result, "%s/.config/%s/%s", home,
-               GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY,
-               GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE);
-  gpr_free(home);
+  gpr_asprintf(&result, "%s/%s", base,
+               GRPC_GOOGLE_CREDENTIALS_PATH_SUFFIX);
+  gpr_free(base);
   return result;
 }
 
-#endif /* GPR_POSIX_FILE */
+#endif /* GRPC_GOOGLE_CREDENTIALS_GENERIC */
diff --git a/src/core/lib/security/credentials/google_default/credentials_windows.c b/src/core/lib/security/credentials/google_default/credentials_windows.c
deleted file mode 100644
index 208b8fd..0000000
--- a/src/core/lib/security/credentials/google_default/credentials_windows.c
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include <grpc/support/port_platform.h>
-
-#ifdef GPR_WINDOWS
-
-#include "src/core/lib/security/credentials/google_default/google_default_credentials.h"
-
-#include <grpc/support/alloc.h>
-#include <grpc/support/log.h>
-#include <grpc/support/string_util.h>
-
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/string.h"
-
-char *grpc_get_well_known_google_credentials_file_path_impl(void) {
-  char *result = NULL;
-  char *appdata_path = gpr_getenv("APPDATA");
-  if (appdata_path == NULL) {
-    gpr_log(GPR_ERROR, "Could not get APPDATA environment variable.");
-    return NULL;
-  }
-  gpr_asprintf(&result, "%s/%s/%s", appdata_path,
-               GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY,
-               GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE);
-  gpr_free(appdata_path);
-  return result;
-}
-
-#endif /* GPR_WINDOWS */
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.h b/src/core/lib/security/credentials/google_default/google_default_credentials.h
index fac4377..bc816bc 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.h
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.h
@@ -34,12 +34,24 @@
 #ifndef GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H
 #define GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H
 
+#include <grpc/support/port_platform.h>
+
 #include "src/core/lib/security/credentials/credentials.h"
 
 #define GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY "gcloud"
 #define GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE \
   "application_default_credentials.json"
 
+#ifdef GPR_WINDOWS
+#define GRPC_GOOGLE_CREDENTIALS_PATH_ENV_VAR "APPDATA"
+#define GRPC_GOOGLE_CREDENTIALS_PATH_SUFFIX GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY "/" GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE
+#define GRPC_GOOGLE_CREDENTIALS_GENERIC 1
+#else
+#define GRPC_GOOGLE_CREDENTIALS_PATH_ENV_VAR "HOME"
+#define GRPC_GOOGLE_CREDENTIALS_PATH_SUFFIX ".config/" GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY "/" GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE
+#define GRPC_GOOGLE_CREDENTIALS_GENERIC 1
+#endif
+
 void grpc_flush_cached_google_default_credentials(void);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H \
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 78fa428..ab7b461 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -195,8 +195,7 @@
   'src/core/lib/security/credentials/credentials.c',
   'src/core/lib/security/credentials/credentials_metadata.c',
   'src/core/lib/security/credentials/fake/fake_credentials.c',
-  'src/core/lib/security/credentials/google_default/credentials_posix.c',
-  'src/core/lib/security/credentials/google_default/credentials_windows.c',
+  'src/core/lib/security/credentials/google_default/credentials_generic.c',
   'src/core/lib/security/credentials/google_default/google_default_credentials.c',
   'src/core/lib/security/credentials/iam/iam_credentials.c',
   'src/core/lib/security/credentials/jwt/json_token.c',