media: Add experimental feature to enable Mojo CDM on desktop Chromium

media/cdm/cdm_adapter_factory.cc

+// Copyright 2017 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.
+
+#include "media/cdm/cdm_adapter_factory.h"
+
+#include "base/base_paths.h"
+#include "base/bind.h"
+#include "base/feature_list.h"
+#include "base/memory/ptr_util.h"
+#include "base/path_service.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "media/base/cdm_factory.h"
+#include "media/base/key_systems.h"
+#include "media/cdm/cdm_adapter.h"
+#include "media/cdm/cdm_paths.h"
+#include "third_party/widevine/cdm/widevine_cdm_common.h"
+
+namespace media {
+
+CdmAdapterFactory::CdmAdapterFactory(
+    CdmAllocator::CreationCB allocator_creation_cb)
+    : allocator_creation_cb_(std::move(allocator_creation_cb)) {
+  DCHECK(allocator_creation_cb_);
+}
+
+CdmAdapterFactory::~CdmAdapterFactory() {}
+
+void CdmAdapterFactory::Create(
+    const std::string& key_system,
+    const GURL& security_origin,
+    const CdmConfig& cdm_config,
+    const SessionMessageCB& session_message_cb,
+    const SessionClosedCB& session_closed_cb,
+    const SessionKeysChangeCB& session_keys_change_cb,
+    const SessionExpirationUpdateCB& session_expiration_update_cb,
+    const CdmCreatedCB& cdm_created_cb) {
+  DVLOG(1) << __FUNCTION__ << ": key_system=" << key_system;
+
+  if (!security_origin.is_valid()) {
+    LOG(ERROR) << "Invalid Origin: " << security_origin;
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(cdm_created_cb, nullptr, "Invalid origin."));
+    return;
+  }
+
+  base::FilePath cdm_path;
+
+#if defined(WIDEVINE_CDM_AVAILABLE)
+  // TODO(xhwang): Remove key-system-specific logic here. We should have the
+  // CDM path forwarded from the browser already. See http://crbug.com/510604
+  if (key_system == kWidevineKeySystem) {
+    // Build the library path for Widevine CDM.
+    // TODO(xhwang): We should have the CDM path forwarded from the browser
+    // already. See http://crbug.com/510604
+    base::FilePath cdm_base_path;
+    base::PathService::Get(base::DIR_MODULE, &cdm_base_path);
+    cdm_base_path = cdm_base_path.Append(
+        GetPlatformSpecificDirectory(kWidevineCdmBaseDirectory));

[jrummell, 2017/05/23 22:23:28]

Can you use DIR_COMPONENT_WIDEVINE_CDM to get the Widevine directory? Doesn't
look like there is anything that uses the library name, but at least simplify
getting the directory.

[xhwang, 2017/05/23 22:31:12]

DIR_COMPONENT_WIDEVINE_CDM points to the component updated CDM, which isn't
always available. Instead, we always have the bundled CDM, which is in the
PlatformSpecificDirectory, and is what we'll use in the current mojo CDM path.
In the future, we'll update CDM registration and pass the CDM path from the
browser so that we don't need this hack here.

+    cdm_path = cdm_base_path.AppendASCII(
+        base::GetNativeLibraryName(kWidevineCdmLibraryName));
+  }
+#endif  // defined(WIDEVINE_CDM_AVAILABLE)
+
+  if (cdm_path.empty()) {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE,
+        base::Bind(cdm_created_cb, nullptr, "Unsupported key system."));
+    return;
+  }
+
+  std::unique_ptr<CdmAllocator> cdm_allocator = allocator_creation_cb_.Run();
+  if (!cdm_allocator) {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE,
+        base::Bind(cdm_created_cb, nullptr, "CDM allocator creation failed."));
+    return;
+  }
+
+  // TODO(xhwang): Hook up auxiliary services, e.g. File IO, output protection,
+  // and platform verification.
+  CdmAdapter::Create(key_system, cdm_path, cdm_config, std::move(cdm_allocator),
+                     CreateCdmFileIOCB(), session_message_cb, session_closed_cb,
+                     session_keys_change_cb, session_expiration_update_cb,
+                     cdm_created_cb);
+}
+
+}  // namespace media