Introduce rtc::ArrayView<T>, which keeps track of an array that it doesn't own

webrtc/base/checks.h

 /*
  *  Copyright 2006 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 146 matching lines @@
 #define RTC_CHECK_NE(val1, val2) RTC_CHECK_OP(NE, !=, val1, val2)
 #define RTC_CHECK_LE(val1, val2) RTC_CHECK_OP(LE, <=, val1, val2)
 #define RTC_CHECK_LT(val1, val2) RTC_CHECK_OP(LT, < , val1, val2)
 #define RTC_CHECK_GE(val1, val2) RTC_CHECK_OP(GE, >=, val1, val2)
 #define RTC_CHECK_GT(val1, val2) RTC_CHECK_OP(GT, > , val1, val2)
 
 // The RTC_DCHECK macro is equivalent to RTC_CHECK except that it only generates
 // code in debug builds. It does reference the condition parameter in all cases,
 // though, so callers won't risk getting warnings about unused variables.
 #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
+#define RTC_DCHECK_IS_ON 1
 #define RTC_DCHECK(condition) RTC_CHECK(condition)
 #define RTC_DCHECK_EQ(v1, v2) RTC_CHECK_EQ(v1, v2)
 #define RTC_DCHECK_NE(v1, v2) RTC_CHECK_NE(v1, v2)
 #define RTC_DCHECK_LE(v1, v2) RTC_CHECK_LE(v1, v2)
 #define RTC_DCHECK_LT(v1, v2) RTC_CHECK_LT(v1, v2)
 #define RTC_DCHECK_GE(v1, v2) RTC_CHECK_GE(v1, v2)
 #define RTC_DCHECK_GT(v1, v2) RTC_CHECK_GT(v1, v2)
 #else
+#define RTC_DCHECK_IS_ON 0
 #define RTC_DCHECK(condition) RTC_EAT_STREAM_PARAMETERS(condition)
 #define RTC_DCHECK_EQ(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) == (v2))
 #define RTC_DCHECK_NE(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) != (v2))
 #define RTC_DCHECK_LE(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) <= (v2))
 #define RTC_DCHECK_LT(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) < (v2))
 #define RTC_DCHECK_GE(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) >= (v2))
 #define RTC_DCHECK_GT(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) > (v2))
 #endif
 
 // This is identical to LogMessageVoidify but in name.
@@ skipping 33 matching lines @@
 // remainder is zero.
 template <typename T>
 inline T CheckedDivExact(T a, T b) {
   RTC_CHECK_EQ(a % b, static_cast<T>(0));
   return a / b;
 }
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_CHECKS_H_