Revert of Change type of pid_diff (int16_t -> uint8_t) according to updates in RTP payload profile. (patchset #3 id:40001 of https://codereview.webrtc.org/1427253002/ )

Reason for revert:
Breaks bot.

Original issue's description:
> Change type of pid_diff (int16_t -> uint8_t) according to updates in RTP payload profile. Max p_diff is 8 bits.
>
> Change type of number of reference pictures (size_t -> uint8_t). Max is 2 bits.
>
> Size of WebRtcRTPHeader: 4352 -> 1784 bytes.
>
> BUG=webrtc:5144, chromium:500602
>
> Committed: https://crrev.com/81c5c7f8157f767747bd97419eb0a589207354cf
> Cr-Commit-Position: refs/heads/master@{#10504}

TBR=stefan@webrtc.org,mflodman@webrtc.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5144, chromium:500602

Review URL: https://codereview.webrtc.org/1423493005

Cr-Commit-Position: refs/heads/master@{#10508}

5 files changed, 17 insertions, 18 deletions

diff --git a/webrtc/modules/interface/module_common_types.h b/webrtc/modules/interface/module_common_types.h
index 8d96870703..e76a71495b 100644
--- a/webrtc/modules/interface/module_common_types.h
+++ b/webrtc/modules/interface/module_common_types.h
@@ -133,7 +133,7 @@ struct GofInfoVP9 {
       temporal_idx[i] = src.temporal_idx[i];
       temporal_up_switch[i] = src.temporal_up_switch[i];
       num_ref_pics[i] = src.num_ref_pics[i];
-      for (uint8_t r = 0; r < num_ref_pics[i]; ++r) {
+      for (size_t r = 0; r < num_ref_pics[i]; ++r) {
         pid_diff[i][r] = src.pid_diff[i][r];
       }
     }
@@ -142,8 +142,8 @@ struct GofInfoVP9 {
   size_t num_frames_in_gof;
   uint8_t temporal_idx[kMaxVp9FramesInGof];
   bool temporal_up_switch[kMaxVp9FramesInGof];
-  uint8_t num_ref_pics[kMaxVp9FramesInGof];
-  uint8_t pid_diff[kMaxVp9FramesInGof][kMaxVp9RefPics];
+  size_t num_ref_pics[kMaxVp9FramesInGof];
+  int16_t pid_diff[kMaxVp9FramesInGof][kMaxVp9RefPics];
 };
 
 struct RTPVideoHeaderVP9 {
@@ -187,9 +187,9 @@ struct RTPVideoHeaderVP9 {
 
   uint8_t gof_idx;  // Index to predefined temporal frame info in SS data.
 
-  uint8_t num_ref_pics;  // Number of reference pictures used by this layer
-                         // frame.
-  uint8_t pid_diff[kMaxVp9RefPics];  // P_DIFF signaled to derive the PictureID
+  size_t num_ref_pics;  // Number of reference pictures used by this layer
+                        // frame.
+  int16_t pid_diff[kMaxVp9RefPics];  // P_DIFF signaled to derive the PictureID
                                      // of the reference pictures.
   int16_t ref_picture_id[kMaxVp9RefPics];  // PictureID of reference pictures.
 
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_format_vp9.cc b/webrtc/modules/rtp_rtcp/source/rtp_format_vp9.cc
index 6a00724096..0e76a8eae8 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_format_vp9.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_format_vp9.cc
@@ -246,7 +246,7 @@ bool WriteRefIndices(const RTPVideoHeaderVP9& vp9,
       vp9.num_ref_pics == 0 || vp9.num_ref_pics > kMaxVp9RefPics) {
     return false;
   }
-  for (uint8_t i = 0; i < vp9.num_ref_pics; ++i) {
+  for (size_t i = 0; i < vp9.num_ref_pics; ++i) {
     bool n_bit = !(i == vp9.num_ref_pics - 1);
     RETURN_FALSE_ON_ERROR(writer->WriteBits(vp9.pid_diff[i], 7));
     RETURN_FALSE_ON_ERROR(writer->WriteBits(n_bit ? 1 : 0, 1));
@@ -301,7 +301,7 @@ bool WriteSsData(const RTPVideoHeaderVP9& vp9, rtc::BitBufferWriter* writer) {
         writer->WriteBits(vp9.gof.temporal_up_switch[i] ? 1 : 0, 1));
     RETURN_FALSE_ON_ERROR(writer->WriteBits(vp9.gof.num_ref_pics[i], 2));
     RETURN_FALSE_ON_ERROR(writer->WriteBits(kReservedBitValue0, 2));
-    for (uint8_t r = 0; r < vp9.gof.num_ref_pics[i]; ++r) {
+    for (size_t r = 0; r < vp9.gof.num_ref_pics[i]; ++r) {
       RETURN_FALSE_ON_ERROR(writer->WriteUInt8(vp9.gof.pid_diff[i][r]));
     }
   }
@@ -466,7 +466,7 @@ bool ParseSsData(rtc::BitBuffer* parser, RTPVideoHeaderVP9* vp9) {
     vp9->gof.temporal_up_switch[i] = u_bit ? true : false;
     vp9->gof.num_ref_pics[i] = r;
 
-    for (uint8_t p = 0; p < vp9->gof.num_ref_pics[i]; ++p) {
+    for (size_t p = 0; p < vp9->gof.num_ref_pics[i]; ++p) {
       uint8_t p_diff;
       RETURN_FALSE_ON_ERROR(parser->ReadUInt8(&p_diff));
       vp9->gof.pid_diff[i][p] = p_diff;
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_format_vp9_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_format_vp9_unittest.cc
index a81e3fec8b..66ab5cdb71 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_format_vp9_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_format_vp9_unittest.cc
@@ -55,7 +55,7 @@ void VerifyHeader(const RTPVideoHeaderVP9& expected,
                 actual.gof.temporal_up_switch[i]);
       EXPECT_EQ(expected.gof.temporal_idx[i], actual.gof.temporal_idx[i]);
       EXPECT_EQ(expected.gof.num_ref_pics[i], actual.gof.num_ref_pics[i]);
-      for (uint8_t j = 0; j < expected.gof.num_ref_pics[i]; j++) {
+      for (size_t j = 0; j < expected.gof.num_ref_pics[i]; j++) {
         EXPECT_EQ(expected.gof.pid_diff[i][j], actual.gof.pid_diff[i][j]);
       }
     }
@@ -545,9 +545,9 @@ TEST_F(RtpDepacketizerVp9Test, ParseLayerInfoWithFlexibleMode) {
 TEST_F(RtpDepacketizerVp9Test, ParseRefIdx) {
   const uint8_t kHeaderLength = 6;
   const int16_t kPictureId = 17;
-  const uint8_t kPdiff1 = 17;
-  const uint8_t kPdiff2 = 18;
-  const uint8_t kPdiff3 = 127;
+  const int16_t kPdiff1 = 17;
+  const int16_t kPdiff2 = 18;
+  const int16_t kPdiff3 = 127;
   uint8_t packet[13] = {0};
   packet[0] = 0xD8;  // I:1 P:1 L:0 F:1 B:1 E:0 V:0 R:0
   packet[1] = 0x80 | ((kPictureId >> 8) & 0x7F);  // Two byte pictureID.
@@ -577,7 +577,7 @@ TEST_F(RtpDepacketizerVp9Test, ParseRefIdx) {
 }
 
 TEST_F(RtpDepacketizerVp9Test, ParseRefIdxFailsWithNoPictureId) {
-  const uint8_t kPdiff = 3;
+  const int16_t kPdiff = 3;
   uint8_t packet[13] = {0};
   packet[0] = 0x58;            // I:0 P:1 L:0 F:1 B:1 E:0 V:0 R:0
   packet[1] = (kPdiff << 1);   // P,F:  P_DIFF:3 N:0
@@ -587,7 +587,7 @@ TEST_F(RtpDepacketizerVp9Test, ParseRefIdxFailsWithNoPictureId) {
 }
 
 TEST_F(RtpDepacketizerVp9Test, ParseRefIdxFailsWithTooManyRefPics) {
-  const uint8_t kPdiff = 3;
+  const int16_t kPdiff = 3;
   uint8_t packet[13] = {0};
   packet[0] = 0xD8;                  // I:1 P:1 L:0 F:1 B:1 E:0 V:0 R:0
   packet[1] = kMaxOneBytePictureId;  // I:    PICTURE ID:127
diff --git a/webrtc/modules/video_coding/main/source/jitter_buffer.cc b/webrtc/modules/video_coding/main/source/jitter_buffer.cc
index b1309aa8fa..bc63411346 100644
--- a/webrtc/modules/video_coding/main/source/jitter_buffer.cc
+++ b/webrtc/modules/video_coding/main/source/jitter_buffer.cc
@@ -168,7 +168,6 @@ void Vp9SsMap::AdvanceFront(uint32_t timestamp) {
   ss_map_[timestamp] = gof;
 }
 
-// TODO(asapersson): Update according to updates in RTP payload profile.
 bool Vp9SsMap::UpdatePacket(VCMPacket* packet) {
   uint8_t gof_idx = packet->codecSpecificHeader.codecHeader.VP9.gof_idx;
   if (gof_idx == kNoGofIdx)
@@ -187,7 +186,7 @@ bool Vp9SsMap::UpdatePacket(VCMPacket* packet) {
 
   // TODO(asapersson): Set vp9.ref_picture_id[i] and add usage.
   vp9->num_ref_pics = it->second.num_ref_pics[gof_idx];
-  for (uint8_t i = 0; i < it->second.num_ref_pics[gof_idx]; ++i) {
+  for (size_t i = 0; i < it->second.num_ref_pics[gof_idx]; ++i) {
     vp9->pid_diff[i] = it->second.pid_diff[gof_idx][i];
   }
   return true;
diff --git a/webrtc/modules/video_coding/main/source/session_info.cc b/webrtc/modules/video_coding/main/source/session_info.cc
index 1e6af8b427..9a1bc54e52 100644
--- a/webrtc/modules/video_coding/main/source/session_info.cc
+++ b/webrtc/modules/video_coding/main/source/session_info.cc
@@ -126,7 +126,7 @@ void VCMSessionInfo::SetGofInfo(const GofInfoVP9& gof_info, size_t idx) {
       gof_info.temporal_up_switch[idx];
   packets_.front().codecSpecificHeader.codecHeader.VP9.num_ref_pics =
       gof_info.num_ref_pics[idx];
-  for (uint8_t i = 0; i < gof_info.num_ref_pics[idx]; ++i) {
+  for (size_t i = 0; i < gof_info.num_ref_pics[idx]; ++i) {
     packets_.front().codecSpecificHeader.codecHeader.VP9.pid_diff[i] =
         gof_info.pid_diff[idx][i];
   }