media: Use platform specific folders for CDMs

media/cdm/ppapi/cdm_paths.gni

+# Copyright 2016 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.
+
+# This file defines output paths for the CDM adapters and CDMs.
+
+# Naming and folder structure below are following the recommendation for chrome
+# components. Component-updated CDMs must following the same recommendation.
+
+# Note: This file must be in sync with cdm_paths.cc
+# TODO(xhwang): Auto generate paths in C++ from build variables so we don't
+# need this note.
+
+# OS name for components is close to "target_os" but has some differences.
+# Explicitly define what we use to avoid confusion.
+if (is_chromeos) {
+  component_os = "cros"
+} else if (is_linux) {
+  component_os = "linux"
+} else if (is_win) {
+  component_os = "win"
+} else if (is_mac) {
+  component_os = "mac"
+} else {
+  component_os = "$target_os"
+}
+
+if (is_win || is_mac) {
+  # Architecture name for components is the same as "<(target_cpu)".
+  _platform_specific_path =
+      "_platform_specific/$component_os" + "_" + "$target_cpu"
+
+  # Path of Clear Key and Widevine CDMs relative to the output dir.
+  clearkey_cdm_path = "ClearKeyCdm/$_platform_specific_path"

[ddorwin, 2016/05/19 00:04:26]

Really dir paths

[xhwang, 2016/05/20 00:22:35]

As discussed offline, we'll keep the current names here.

+  widevine_cdm_path = "WidevineCdm/$_platform_specific_path"

[ddorwin, 2016/05/19 00:04:26]

Could we then add a define that gets used in C++ files rather than rebuilding
this in the .cc file?

Mayb we can also make any code that wants to use the path depend on this file,
addressing the concern about broad media dependencies.

[xhwang, 2016/05/20 00:22:35]

I thought about that but there are issues with that approach, e.g.
- We'll end up needing to use pulic_config to populate that macro/define up.
- We'll use macros in source code which isn't recommended
- We have to deal with path logic in the macro, e.g. window/posix path with
slash/backslash.

+} else {
+  clearkey_cdm_path = "."
+  widevine_cdm_path = "."
+}