Make peeking before the head of OffsetByteQueue a hard error.

media/mp4/offset_byte_queue_unittest.cc

Index: media/mp4/offset_byte_queue_unittest.cc
diff --git a/media/mp4/offset_byte_queue_unittest.cc b/media/mp4/offset_byte_queue_unittest.cc
index 3a9b133b281a860ac69e1b1a4d4a69591a36057d..ac4a4627379c056eb6710ab5cc8b99ace2a24840 100644
--- a/media/mp4/offset_byte_queue_unittest.cc
+++ b/media/mp4/offset_byte_queue_unittest.cc
@@ -44,14 +44,10 @@ TEST_F(OffsetByteQueueTest, TestSetUp) {
   EXPECT_EQ(255, buf[size-1]);
 }
 
-TEST_F(OffsetByteQueueTest, TestPeekAt) {
+TEST_F(OffsetByteQueueTest, PeekAtDeathTest) {
   const uint8* buf;
   int size;
 
-  queue_->PeekAt(128, &buf, &size);
-  EXPECT_EQ(NULL, buf);
-  EXPECT_EQ(0, size);
-
   queue_->PeekAt(400, &buf, &size);
   EXPECT_EQ(queue_->tail() - 400, size);
   EXPECT_EQ(400 - 256, buf[0]);
@@ -59,6 +55,9 @@ TEST_F(OffsetByteQueueTest, TestPeekAt) {
   queue_->PeekAt(512, &buf, &size);
   EXPECT_EQ(NULL, buf);
   EXPECT_EQ(0, size);
+
+  // Peeking before current head should be an error
+  ASSERT_DEATH(queue_->PeekAt(128, &buf, &size), "offset >= head");

[acolwell GONE FROM CHROMIUM, 2012/07/31 19:27:44]

Remove this since you said this situation only happens as a result of a coding
error. No need to test that the DCHECK is there.

 }
 
 TEST_F(OffsetByteQueueTest, TestTrim) {