media: Verify CDM Host files

content/common/media/cdm_host_file.cc

Index: content/common/media/cdm_host_file.cc
diff --git a/content/common/media/cdm_host_file.cc b/content/common/media/cdm_host_file.cc
new file mode 100644
index 0000000000000000000000000000000000000000..347455ed0461cd5fc6b34ab6f5cfd6da46022bc5
--- /dev/null
+++ b/content/common/media/cdm_host_file.cc
@@ -0,0 +1,71 @@
+// 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.
+
+#include "content/common/media/cdm_host_file.h"
+
+#include <memory>
+
+#include "base/command_line.h"
+#include "base/feature_list.h"
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "media/base/media_switches.h"
+#include "media/cdm/api/content_decryption_module_ext.h"
+
+namespace content {
+
+namespace {
+
+bool IgnoreMissingCdmHostFile() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kIgnoreMissingCdmHostFile);
+}
+
+}  // namespace
+
+std::unique_ptr<CdmHostFile> CdmHostFile::Create(
+    const base::FilePath& file_path,
+    const base::FilePath& sig_file_path) {
+  // Open file at |file_path|.
+  base::File file(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
+  if (!file.IsValid()) {
+    DVLOG(1) << "Failed to open file at " << file_path.MaybeAsASCII();
+    return nullptr;
+  }
+
+  // Also open the sig file at |sig_file_path|.
+  base::File sig_file(sig_file_path,
+                      base::File::FLAG_OPEN | base::File::FLAG_READ);
+  if (!sig_file.IsValid()) {
+    DVLOG(1) << "Failed to open sig file at " << sig_file_path.MaybeAsASCII();
+    if (!IgnoreMissingCdmHostFile())
+      return nullptr;
+
+    DVLOG(1) << "Ignoring sig file failure at " << sig_file_path.MaybeAsASCII();
+  }
+
+  return std::unique_ptr<CdmHostFile>(
+      new CdmHostFile(file_path, std::move(file), std::move(sig_file)));
+}
+
+cdm::HostFile CdmHostFile::TakePlatformFile() {
+  return cdm::HostFile(file_path_.value().c_str(), file_.TakePlatformFile(),
+                       sig_file_.TakePlatformFile());
+}
+
+CdmHostFile::CdmHostFile(const base::FilePath& file_path,
+                         base::File file,
+                         base::File sig_file)
+    : file_path_(file_path),
+      file_(std::move(file)),
+      sig_file_(std::move(sig_file)) {
+  DVLOG(1) << __func__ << ": " << file_path_.value();
+  DCHECK(!file_path_.empty()) << "File path is empty.";
+  DCHECK(file_.IsValid()) << "Invalid file.";
+
+  if (!IgnoreMissingCdmHostFile())
+    DCHECK(sig_file_.IsValid()) << "Invalid signature file.";
+}
+
+}  // namespace content