Adds 'virtual' and 'const' modifiers to methods in wv_cas_ecm.

-------------
Expose header files under export/exported_root/util in media_cas_packager_sdk because util::Status is used in wv_cas_ecm.h

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=218632176

media_cas_packager_sdk/public/wv_cas_ecm.h

@@ -51,8 +51,8 @@ class WvCasEcm {
   //
   // Note:
   // - 'even'/'odd' key in the ECM will be be encrypted using AEC_CBC
-  util::Status Initialize(int content_iv_size, bool key_rotation_enabled,
+  virtual util::Status Initialize(int content_iv_size,
-                          int crypto_mode);
+                                  bool key_rotation_enabled, int crypto_mode);
 
   // Generate an ECM containing two keys (even and odd). Can be called when
   // |key_rotation_enabled| is initialized to 'true'.
@@ -74,11 +74,13 @@ class WvCasEcm {
   //   and |odd_key| in the ECM
   // - Size of |even_content_iv| and |odd_content_iv| must match
   //   |content_iv_size| set during initialization
-  util::Status GenerateEcm(const std::string& even_key,
+  virtual util::Status GenerateEcm(const std::string& even_key,
-                           const std::string& even_content_iv, const std::string& odd_key,
+                                   const std::string& even_content_iv,
+                                   const std::string& odd_key,
                                    const std::string& odd_content_iv,
                                    const std::string& entitlement_key_id,
-                           const std::string& entitlement_key, std::string* ecm);
+                                   const std::string& entitlement_key,
+                                   std::string* ecm) const;
 
   // Generate an ECM containing only a singe even key. Can be called when
   // |key_rotation_enabled| is initialized to 'false'.
@@ -96,10 +98,11 @@ class WvCasEcm {
   // Note:
   // - Size of |even_content_iv| and |odd_content_iv| must match
   //   |content_iv_size| set during initialization
-  util::Status GenerateSingleKeyEcm(const std::string& even_key,
+  virtual util::Status GenerateSingleKeyEcm(const std::string& even_key,
                                             const std::string& even_content_iv,
                                             const std::string& entitlement_key_id,
-                                    const std::string& entitlement_key, std::string* ecm);
+                                            const std::string& entitlement_key,
+                                            std::string* ecm) const;
 
  private:
   bool initialized_ = false;

util/error_space.h

@@ -0,0 +1,83 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright 2017 Google LLC.
+//
+// This software is licensed under the terms defined in the Widevine Master
+// License Agreement. For a copy of this agreement, please contact
+// widevine-licensing@google.com.
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef UTIL_ERROR_SPACE_H_
+#define UTIL_ERROR_SPACE_H_
+
+#include <string>
+
+namespace widevine {
+namespace util {
+
+class ErrorSpace {
+ public:
+  std::string SpaceName() const { return space_name_func_(this); }
+  std::string String(int code) const { return code_to_string_func_(this, code); }
+
+ protected:
+  // typedef instead of using statements for SWIG compatibility.
+  typedef std::string (*SpaceNameFunc)(const ErrorSpace* space);
+  typedef std::string (*CodeToStringFunc)(const ErrorSpace* space, int code);
+  constexpr ErrorSpace(SpaceNameFunc space_name_func,
+                       CodeToStringFunc code_to_string_func)
+      : space_name_func_(space_name_func),
+        code_to_string_func_(code_to_string_func) {}
+
+ private:
+  const SpaceNameFunc space_name_func_;
+  const CodeToStringFunc code_to_string_func_;
+};
+
+// Manages creation of error space subclasses.
+template <typename T>
+class ErrorSpaceImpl : public ErrorSpace {
+ public:
+  constexpr ErrorSpaceImpl()
+      : ErrorSpace(&ErrorSpaceImpl::SpaceNameImpl,
+                   &ErrorSpaceImpl::CodeToStringImpl) {}
+
+  // Returns the canonical instance of the `T` error space.
+  static constexpr const T* Get();
+
+ private:
+  // These functions adapt the stateful implementation that takes a space
+  // pointer to stateless static methods, so that clients of ErrorSpaceImpl are
+  // safe to have constexpr global instances.
+  static std::string SpaceNameImpl(const ErrorSpace* /*space*/) {
+    return T::SpaceName();
+  }
+
+  static std::string CodeToStringImpl(const ErrorSpace* /*space*/, int code) {
+    return T::CodeToString(code);
+  }
+};
+
+namespace internal {
+
+// Provides a global constexpr instance of the error space `T`.
+// We need the indirection because ErrorSpaceImpl can't declare constexpr
+// instances of T since it is not yet fully declared.
+template <typename T>
+struct ErrorSpaceInstance {
+  static constexpr T value = {};
+};
+
+template <typename T>
+constexpr T ErrorSpaceInstance<T>::value;
+
+}  // namespace internal
+
+template <typename T>
+constexpr const T* ErrorSpaceImpl<T>::Get() {
+  return &internal::ErrorSpaceInstance<T>::value;
+}
+
+}  // namespace util
+}  // namespace widevine
+
+#endif  // UTIL_ERROR_SPACE_H_

util/status.h

@@ -0,0 +1,119 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright 2017 Google LLC.
+//
+// This software is licensed under the terms defined in the Widevine Master
+// License Agreement. For a copy of this agreement, please contact
+// widevine-licensing@google.com.
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef UTIL_STATUS_H_
+#define UTIL_STATUS_H_
+
+#include <string>
+
+#include "util/error_space.h"
+
+namespace widevine {
+namespace util {
+namespace error {
+
+enum StatusCode {
+  // Success.
+  OK = 0,
+
+  // Client specified an invalid argument.
+  INVALID_ARGUMENT = 3,
+
+  // Some requested entity (e.g., file or directory) was not found.
+  NOT_FOUND = 5,
+
+  // Some entity that we attempted to create (e.g., file or directory)
+  // already exists.
+  ALREADY_EXISTS = 6,
+
+  // The caller does not have permission to execute the specified
+  // operation.  PERMISSION_DENIED must not be used for rejections
+  // caused by exhausting some resource (use RESOURCE_EXHAUSTED
+  // instead for those errors).
+  PERMISSION_DENIED = 7,
+
+  // Operation is not implemented or not supported/enabled in this service.
+  UNIMPLEMENTED = 12,
+
+  // Internal errors.  Means some invariants expected by underlying
+  // system has been broken.  If you see one of these errors,
+  // something is very broken.
+  INTERNAL = 13,
+
+  // Operation is not implemented or not supported/enabled in this service.
+  UNAVAILABLE = 14,
+
+  // Number of generic (non license related) errors.
+  NUM_ERRORS,
+};
+
+}  // namespace error
+
+class GenericErrorSpace : public ErrorSpaceImpl<GenericErrorSpace> {
+ public:
+  static std::string SpaceName();
+  static std::string CodeToString(int code);
+};
+
+class Status {
+ public:
+  Status() : status_code_(error::OK) {}
+  ~Status() {}
+  explicit Status(error::StatusCode c) : status_code_(c) {}
+  Status(error::StatusCode c, const std::string& error_message)
+      : status_code_(c), error_message_(error_message) {}
+  Status(const ErrorSpace* e, error::StatusCode c,
+         const std::string& error_message) {
+    SetError(e, c, error_message);
+  }
+  Status(const ErrorSpace* e, int error, const std::string& error_message) {
+    SetError(e, error, error_message);
+  }
+  void SetError(const ErrorSpace* e, int c, const std::string& error_message) {
+    error_space_ = e;
+    status_code_ = c;
+    error_message_ = error_message;
+  }
+
+  bool ok() const { return status_code_ == error::OK; }
+  const ErrorSpace* error_space() const { return error_space_; }
+  static const ErrorSpace* canonical_space() {
+    return GenericErrorSpace::Get();
+  }
+  std::string ToString() const;
+  std::string error_message() const { return error_message_; }
+  int error_code() const { return status_code_; }
+
+ private:
+  const ErrorSpace* error_space_ = GenericErrorSpace::Get();
+  int status_code_;
+  std::string error_message_;
+};  // class Status
+
+inline Status OkStatus() { return Status(); }
+
+// Here error_message_ is ignored during comparison.
+inline bool operator==(const Status& s1, const Status& s2) {
+  return s1.error_space() == s2.error_space() &&
+         s1.error_code() == s2.error_code();
+}
+inline bool operator!=(const Status& s1, const Status& s2) {
+  return s1.error_space() != s2.error_space() ||
+         s1.error_code() != s2.error_code();
+}
+
+// Prints a human-readable representation of 'x' to 'os'.
+std::ostream& operator<<(std::ostream& os, const Status& x);
+
+#define CHECK_OK(expression) CHECK_EQ(util::error::OK, expression.error_code())
+
+
+}  // namespace util
+}  // namespace widevine
+
+#endif  // UTIL_STATUS_H_