Add [c]begin() and [c]end() member functions to rtc::Buffer

webrtc/base/buffer_unittest.cc

 /*
  *  Copyright 2004 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 338 matching lines @@
 
   for (size_t i = 0; i != 7u; ++i) {
     buf[i] = kTestData[i];
   }
 
   for (size_t i = 0; i != 7u; ++i) {
     EXPECT_EQ(buf[i], kTestData[i]);
   }
 }
 
+TEST(BufferTest, TestBeginEnd) {
+  const Buffer cbuf(kTestData);
+  Buffer buf(kTestData);
+  auto b1 = cbuf.begin();
+  for (auto& x : buf) {
+    EXPECT_EQ(*b1, x);
+    ++b1;
+    ++x;
+  }
+  EXPECT_EQ(cbuf.end(), b1);
+  auto b2 = buf.begin();
+  for (auto& y : cbuf) {
+    EXPECT_EQ(*b2, y + 1);
+    ++b2;
+  }
+  EXPECT_EQ(buf.end(), b2);
+}
+
 TEST(BufferTest, TestInt16) {
   static constexpr int16_t test_data[] = {14, 15, 16, 17, 18};
   BufferT<int16_t> buf(test_data);
   EXPECT_EQ(buf.size(), 5u);
   EXPECT_EQ(buf.capacity(), 5u);
   EXPECT_NE(buf.data(), nullptr);
   EXPECT_FALSE(buf.empty());
   for (size_t i = 0; i != buf.size(); ++i) {
     EXPECT_EQ(test_data[i], buf[i]);
   }
@@ skipping 41 matching lines @@
   BufferT<BloodStone*> buf2(4);
   for (size_t i = 0; i < buf2.size(); ++i) {
     buf2[i] = &buf[i];
   }
   static const char kObsidian[] = "obsidian";
   buf2[2]->stone = kObsidian;
   EXPECT_EQ(kObsidian, buf[2].stone);
 }
 
 }  // namespace rtc