Reland 596ff54335b2a1b393af10657bc4945114f3beed - Split API bundle generation steps

chrome/common/extensions/api/schemas.gni

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/features.gni")
+
+gypi_values = exec_script(
+    "//build/gypi_to_gn.py",
+    [ rebase_path("schemas.gypi") ],
+    "scope",
+    [ "schemas.gypi" ])
+
+# Common sources that are both bundled and compiled.
+if (is_android) {
+  # Should be eliminated. See crbug.com/305852.
+  sources = gypi_values.android_schema_files
+} else {
+  sources = gypi_values.main_schema_files
+  if (is_chromeos) {
+    sources += gypi_values.chromeos_schema_files
+    if (is_chrome_branded) {
+      sources += gypi_values.chromeos_branded_schema_files
+    }
+  }
+  if (enable_webrtc) {
+    sources += gypi_values.webrtc_schema_files
+  }
+}
+
+if (!is_android) {
+  uncompiled_sources = gypi_values.main_non_compiled_schema_files
+}
+
+root_namespace = "extensions::api::%(namespace)s"