Revert of Rename RTPVideoHeader.isFirstPacket to .is_first_packet_in_frame. (patchset #1 id:1 of https://codereview.webrtc.org/2574943003/ )

Reason for revert:
breaks downstream project.

Can you make this change in a compatible way using anonymous union:
union {
  bool is_first_packet_in_frame;
  RTC_DEPRECATED bool isFirstPacket;
};
(unfortunetly this this treak breaks braced initialization in rtp_rtcp_impl_unittest.cc,
so that should be rewritting in a more classic way)

Original issue's description:
> Rename RTPVideoHeader.isFirstPacket to .is_first_packet_in_frame.
>
> Name should represent the actual meaning.
>
> BUG=None
>
> Review-Url: https://codereview.webrtc.org/2574943003
> Cr-Commit-Position: refs/heads/master@{#15684}
> Committed: https://chromium.googlesource.com/external/webrtc/+/efde90838055f44ca05863ba020ca02c88b6d14c

TBR=stefan@webrtc.org,sprang@webrtc.org,johan@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review-Url: https://codereview.webrtc.org/2589783003
Cr-Commit-Position: refs/heads/master@{#15686}
diff --git a/webrtc/modules/video_coding/session_info_unittest.cc b/webrtc/modules/video_coding/session_info_unittest.cc
index 6705a78..2cefc06 100644
--- a/webrtc/modules/video_coding/session_info_unittest.cc
+++ b/webrtc/modules/video_coding/session_info_unittest.cc
@@ -114,7 +114,7 @@
 };
 
 TEST_F(TestSessionInfo, TestSimpleAPIs) {
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.seqNum = 0xFFFE;
   packet_.sizeBytes = packet_buffer_size();
   packet_.frameType = kVideoFrameKey;
@@ -125,7 +125,7 @@
   EXPECT_FALSE(session_.HaveLastPacket());
   EXPECT_EQ(kVideoFrameKey, session_.FrameType());
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = true;
   packet_.seqNum += 1;
   EXPECT_EQ(packet_buffer_size(),
@@ -137,7 +137,7 @@
 
   // Insert empty packet which will be the new high sequence number.
   // To make things more difficult we will make sure to have a wrap here.
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = true;
   packet_.seqNum = 2;
   packet_.sizeBytes = 0;
@@ -149,14 +149,14 @@
 
 TEST_F(TestSessionInfo, NormalOperation) {
   packet_.seqNum = 0xFFFF;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = false;
   FillPacket(0);
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   for (int i = 1; i < 9; ++i) {
     packet_.seqNum += 1;
     FillPacket(i);
@@ -181,7 +181,7 @@
 
 TEST_F(TestSessionInfo, ErrorsEqualDecodableState) {
   packet_.seqNum = 0xFFFF;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(3);
   EXPECT_EQ(packet_buffer_size(),
@@ -192,7 +192,7 @@
 
 TEST_F(TestSessionInfo, SelectiveDecodableState) {
   packet_.seqNum = 0xFFFF;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   frame_data.rolling_average_packets_per_frame = 11;
@@ -204,13 +204,13 @@
 
   packet_.seqNum -= 1;
   FillPacket(0);
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(
                 packet_, frame_buffer_, kSelectiveErrors, frame_data)));
   EXPECT_TRUE(session_.decodable());
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.seqNum += 1;
   for (int i = 2; i < 8; ++i) {
     packet_.seqNum += 1;
@@ -231,7 +231,7 @@
 
 TEST_F(TestSessionInfo, OutOfBoundsPackets1PacketFrame) {
   packet_.seqNum = 0x0001;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
@@ -239,13 +239,13 @@
                                                       kNoErrors, frame_data)));
 
   packet_.seqNum = 0x0004;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(
       -3, session_.InsertPacket(packet_, frame_buffer_, kNoErrors, frame_data));
   packet_.seqNum = 0x0000;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(
@@ -254,14 +254,14 @@
 
 TEST_F(TestSessionInfo, SetMarkerBitOnce) {
   packet_.seqNum = 0x0005;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
   ++packet_.seqNum;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(
@@ -271,7 +271,7 @@
 TEST_F(TestSessionInfo, OutOfBoundsPacketsBase) {
   // Allow packets in the range 5-6.
   packet_.seqNum = 0x0005;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
@@ -279,20 +279,20 @@
                                                       kNoErrors, frame_data)));
   // Insert an older packet with a first packet set.
   packet_.seqNum = 0x0004;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(
       -3, session_.InsertPacket(packet_, frame_buffer_, kNoErrors, frame_data));
   packet_.seqNum = 0x0006;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
   packet_.seqNum = 0x0008;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(
@@ -301,7 +301,7 @@
 
 TEST_F(TestSessionInfo, OutOfBoundsPacketsWrap) {
   packet_.seqNum = 0xFFFE;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
@@ -309,27 +309,27 @@
                                                       kNoErrors, frame_data)));
 
   packet_.seqNum = 0x0004;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
   packet_.seqNum = 0x0002;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   ASSERT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
   packet_.seqNum = 0xFFF0;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(
       -3, session_.InsertPacket(packet_, frame_buffer_, kNoErrors, frame_data));
   packet_.seqNum = 0x0006;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(
@@ -340,7 +340,7 @@
   // Insert out of bound regular packets, and then the first and last packet.
   // Verify that correct bounds are maintained.
   packet_.seqNum = 0x0003;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
@@ -348,27 +348,27 @@
                                                       kNoErrors, frame_data)));
   // Insert an older packet with a first packet set.
   packet_.seqNum = 0x0005;
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
   packet_.seqNum = 0x0004;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(
       -3, session_.InsertPacket(packet_, frame_buffer_, kNoErrors, frame_data));
   packet_.seqNum = 0x0010;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
   packet_.seqNum = 0x0008;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = true;
   FillPacket(1);
   EXPECT_EQ(packet_buffer_size(),
@@ -376,7 +376,7 @@
                                                       kNoErrors, frame_data)));
 
   packet_.seqNum = 0x0009;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.markerBit = false;
   FillPacket(1);
   EXPECT_EQ(
@@ -384,7 +384,7 @@
 }
 
 TEST_F(TestNalUnits, OnlyReceivedEmptyPacket) {
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluComplete;
   packet_.frameType = kEmptyFrame;
   packet_.sizeBytes = 0;
@@ -398,7 +398,7 @@
 }
 
 TEST_F(TestNalUnits, OneIsolatedNaluLoss) {
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.completeNALU = kNaluComplete;
   packet_.seqNum = 0;
   packet_.markerBit = false;
@@ -407,7 +407,7 @@
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluComplete;
   packet_.seqNum += 2;
   packet_.markerBit = true;
@@ -425,7 +425,7 @@
 }
 
 TEST_F(TestNalUnits, LossInMiddleOfNalu) {
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.completeNALU = kNaluComplete;
   packet_.seqNum = 0;
   packet_.markerBit = false;
@@ -434,7 +434,7 @@
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluEnd;
   packet_.seqNum += 2;
   packet_.markerBit = true;
@@ -450,7 +450,7 @@
 }
 
 TEST_F(TestNalUnits, StartAndEndOfLastNalUnitLost) {
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.completeNALU = kNaluComplete;
   packet_.seqNum = 0;
   packet_.markerBit = false;
@@ -459,7 +459,7 @@
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluIncomplete;
   packet_.seqNum += 2;
   packet_.markerBit = false;
@@ -476,7 +476,7 @@
 
 TEST_F(TestNalUnits, ReorderWrapNoLoss) {
   packet_.seqNum = 0xFFFF;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluIncomplete;
   packet_.seqNum += 1;
   packet_.markerBit = false;
@@ -485,7 +485,7 @@
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = true;
+  packet_.isFirstPacket = true;
   packet_.completeNALU = kNaluComplete;
   packet_.seqNum -= 1;
   packet_.markerBit = false;
@@ -494,7 +494,7 @@
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluEnd;
   packet_.seqNum += 2;
   packet_.markerBit = true;
@@ -511,7 +511,7 @@
 
 TEST_F(TestNalUnits, WrapLosses) {
   packet_.seqNum = 0xFFFF;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluIncomplete;
   packet_.markerBit = false;
   FillPacket(1);
@@ -519,7 +519,7 @@
             static_cast<size_t>(session_.InsertPacket(packet_, frame_buffer_,
                                                       kNoErrors, frame_data)));
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluEnd;
   packet_.seqNum += 2;
   packet_.markerBit = true;
@@ -535,7 +535,7 @@
 TEST_F(TestNalUnits, ReorderWrapLosses) {
   packet_.seqNum = 0xFFFF;
 
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluEnd;
   packet_.seqNum += 2;
   packet_.markerBit = true;
@@ -545,7 +545,7 @@
                                                       kNoErrors, frame_data)));
 
   packet_.seqNum -= 2;
-  packet_.is_first_packet_in_frame = false;
+  packet_.isFirstPacket = false;
   packet_.completeNALU = kNaluIncomplete;
   packet_.markerBit = false;
   FillPacket(1);