[gaia] Introduce Gaia URLs config

Currently, there are 5 different URL switches in
google_apis/gaia/gaia_switches.cc that need to be manually set to set
non-prod Gaia environment. This CL introduces a new command line switch
to rule them all:

--gaia-config=gaia_test.json

A JSON config file allows to override all URLs available in
google_apis/gaia/gaia_urls.h. For a format example take a look at
google_apis/test/data/gaia/all_urls.json.

The proposed design was chosen because of the following:
- It allows to override each individual URL separately without bloating
the command line. This can be useful for developers who run their own
test instances.
- It makes easy to hide test URLs used at Google in the internal repo.

Bug: 1072731
Change-Id: I3c32c53f9dc27b01ceab8ef57eb71c00d5df0977
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2166197
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771605}

google_apis/BUILD.gn

@@ -213,6 +213,7 @@ test("google_apis_unittests") {
     "gaia/gaia_auth_fetcher_unittest.cc",
     "gaia/gaia_auth_util_unittest.cc",
     "gaia/gaia_oauth_client_unittest.cc",
+    "gaia/gaia_urls_unittest.cc",
     "gaia/google_service_auth_error_unittest.cc",
     "gaia/oauth2_access_token_fetcher_impl_unittest.cc",
     "gaia/oauth2_access_token_manager_unittest.cc",
@@ -225,8 +226,6 @@ test("google_apis_unittests") {
     "google_api_keys_unittest.h",
   ]
 
-  data = [ "test/" ]
-
   configs += [ ":key_defines" ]
 
   deps = [
@@ -241,6 +240,12 @@ test("google_apis_unittests") {
     "//testing/gtest",
   ]
 
+  if (is_ios) {
+    deps += [ ":google_apis_unittest_bundle_data" ]
+  } else {
+    data = [ "test/" ]
+  }
+
   if (enable_extensions) {
     deps += [ "//google_apis/drive:drive_unittests" ]
   }
@@ -253,3 +258,19 @@ test("google_apis_unittests") {
     deps += [ "//third_party/ocmock" ]
   }
 }
+
+bundle_data("google_apis_unittest_bundle_data") {
+  testonly = true
+  sources = [
+    "test/data/gaia/all_base_urls.json",
+    "test/data/gaia/all_urls.json",
+    "test/data/gaia/bad_url.json",
+    "test/data/gaia/bad_url_key.json",
+    "test/data/gaia/bad_urls_key.json",
+    "test/data/gaia/not_a_json.txt",
+    "test/data/gaia/one_base_url.json",
+    "test/data/gaia/one_url.json",
+  ]
+  outputs = [ "{{bundle_resources_dir}}/" +
+              "{{source_root_relative_dir}}/{{source_file_part}}" ]
+}

google_apis/gaia/gaia_switches.cc

@@ -6,6 +6,7 @@
 
 namespace switches {
 
+const char kGaiaConfig[] = "gaia-config";
 const char kGoogleUrl[]                     = "google-url";
 const char kGaiaUrl[]                       = "gaia-url";
 const char kGoogleApisUrl[]                 = "google-apis-url";

google_apis/gaia/gaia_switches.h

@@ -7,6 +7,10 @@
 
 namespace switches {
 
+// Specifies the path to a config file containing GAIA urls.
+// See "google_apis/test/data/gaia/all_urls.json" for a format example.
+extern const char kGaiaConfig[];
+
 // Specifies the domain of the SAPISID cookie. The default value is
 // "http://.google.com".
 extern const char kGoogleUrl[];