media config: expand is_encrypted to a struct.

media/base/encryption_scheme.cc

+// Copyright 2015 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/base/encryption_scheme.h"
+
+namespace media {
+
+EncryptionScheme::PatternSpec::PatternSpec()
+    : encrypt_blocks_(0), skip_blocks_(0) {}
+
+EncryptionScheme::PatternSpec::PatternSpec(uint32_t encrypt_blocks,
+                                           uint32_t skip_blocks)
+    : encrypt_blocks_(encrypt_blocks), skip_blocks_(skip_blocks) {}
+
+EncryptionScheme::PatternSpec::~PatternSpec() {}
+
+bool EncryptionScheme::PatternSpec::Matches(const PatternSpec& other) const {
+  return encrypt_blocks_ == other.encrypt_blocks() &&
+         skip_blocks_ == other.skip_blocks();
+}
+
+bool EncryptionScheme::PatternSpec::IsInEffect() const {
+  return encrypt_blocks_ != 0 || skip_blocks_ != 0;
+}
+
+EncryptionScheme::EncryptionScheme() : mode_(kCipherModeNone), pattern_() {}
+
+EncryptionScheme::EncryptionScheme(bool is_encrypted)
+    : mode_(is_encrypted ? kCipherModeAesCtr : kCipherModeNone) {}
+
+EncryptionScheme::EncryptionScheme(CipherMode mode) : mode_(mode), pattern_() {}
+
+EncryptionScheme::EncryptionScheme(CipherMode mode, const PatternSpec& pattern)
+    : mode_(mode), pattern_(pattern) {}
+
+EncryptionScheme::~EncryptionScheme() {}
+
+void EncryptionScheme::Initialize(CipherMode mode, const PatternSpec& pattern) {
+  mode_ = mode;
+  pattern_ = pattern;
+}
+
+bool EncryptionScheme::Matches(const EncryptionScheme& other) const {
+  return mode_ == other.mode_ && pattern_.Matches(other.pattern_);
+}
+
+bool EncryptionScheme::is_encrypted() const {
+  return mode_ != kCipherModeNone;
+}
+
+}  // namespace media