Update BitBuffer methods to style guide

Specifically, use reference instead of pointer for out parameter
and place the out parameter last, for the following methods

ReadUInt8
ReadUInt16
ReadUInt32
ReadBits
PeekBits
ReadNonSymmetric
ReadSignedExponentialGolomb
ReadExponentialGolomb

Bug: webrtc:11933
Change-Id: I3f1efe3e29155985277b0cd18700ddea25fe7914
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/218504
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34037}
diff --git a/rtc_base/bit_buffer.h b/rtc_base/bit_buffer.h
index 045d369..388218e 100644
--- a/rtc_base/bit_buffer.h
+++ b/rtc_base/bit_buffer.h
@@ -14,6 +14,7 @@
 #include <stddef.h>  // For size_t.
 #include <stdint.h>  // For integer types.
 
+#include "absl/base/attributes.h"
 #include "rtc_base/constructor_magic.h"
 
 namespace rtc {
@@ -38,20 +39,35 @@
 
   // Reads byte-sized values from the buffer. Returns false if there isn't
   // enough data left for the specified type.
-  bool ReadUInt8(uint8_t* val);
-  bool ReadUInt16(uint16_t* val);
-  bool ReadUInt32(uint32_t* val);
+  bool ReadUInt8(uint8_t& val);
+  bool ReadUInt16(uint16_t& val);
+  bool ReadUInt32(uint32_t& val);
+  ABSL_DEPRECATED("") bool ReadUInt8(uint8_t* val) {
+    return val ? ReadUInt8(*val) : false;
+  }
+  ABSL_DEPRECATED("") bool ReadUInt16(uint16_t* val) {
+    return val ? ReadUInt16(*val) : false;
+  }
+  ABSL_DEPRECATED("") bool ReadUInt32(uint32_t* val) {
+    return val ? ReadUInt32(*val) : false;
+  }
 
   // Reads bit-sized values from the buffer. Returns false if there isn't enough
   // data left for the specified bit count.
-  bool ReadBits(uint32_t* val, size_t bit_count);
-  bool ReadBits(uint64_t* val, size_t bit_count);
+  bool ReadBits(size_t bit_count, uint32_t& val);
+  bool ReadBits(size_t bit_count, uint64_t& val);
+  ABSL_DEPRECATED("") bool ReadBits(uint32_t* val, size_t bit_count) {
+    return val ? ReadBits(bit_count, *val) : false;
+  }
 
   // Peeks bit-sized values from the buffer. Returns false if there isn't enough
   // data left for the specified number of bits. Doesn't move the current
   // offset.
-  bool PeekBits(uint32_t* val, size_t bit_count);
-  bool PeekBits(uint64_t* val, size_t bit_count);
+  bool PeekBits(size_t bit_count, uint32_t& val);
+  bool PeekBits(size_t bit_count, uint64_t& val);
+  ABSL_DEPRECATED("") bool PeekBits(uint32_t* val, size_t bit_count) {
+    return val ? PeekBits(bit_count, *val) : false;
+  }
 
   // Reads value in range [0, num_values - 1].
   // This encoding is similar to ReadBits(val, Ceil(Log2(num_values)),
@@ -63,7 +79,11 @@
   // Value v in range [k, num_values - 1] is encoded as (v+k) in n bits.
   // https://aomediacodec.github.io/av1-spec/#nsn
   // Returns false if there isn't enough data left.
-  bool ReadNonSymmetric(uint32_t* val, uint32_t num_values);
+  bool ReadNonSymmetric(uint32_t num_values, uint32_t& val);
+  ABSL_DEPRECATED("")
+  bool ReadNonSymmetric(uint32_t* val, uint32_t num_values) {
+    return val ? ReadNonSymmetric(num_values, *val) : false;
+  }
 
   // Reads the exponential golomb encoded value at the current offset.
   // Exponential golomb values are encoded as:
@@ -73,11 +93,18 @@
   // and increment the result by 1.
   // Returns false if there isn't enough data left for the specified type, or if
   // the value wouldn't fit in a uint32_t.
-  bool ReadExponentialGolomb(uint32_t* val);
+  bool ReadExponentialGolomb(uint32_t& val);
+  ABSL_DEPRECATED("") bool ReadExponentialGolomb(uint32_t* val) {
+    return val ? ReadExponentialGolomb(*val) : false;
+  }
+
   // Reads signed exponential golomb values at the current offset. Signed
   // exponential golomb values are just the unsigned values mapped to the
   // sequence 0, 1, -1, 2, -2, etc. in order.
-  bool ReadSignedExponentialGolomb(int32_t* val);
+  bool ReadSignedExponentialGolomb(int32_t& val);
+  ABSL_DEPRECATED("") bool ReadSignedExponentialGolomb(int32_t* val) {
+    return val ? ReadSignedExponentialGolomb(*val) : false;
+  }
 
   // Moves current position |byte_count| bytes forward. Returns false if
   // there aren't enough bytes left in the buffer.