Accept and ignore PRIORITY frames in SPDY4+.

net/spdy/spdy_framer.cc

Index: net/spdy/spdy_framer.cc
diff --git a/net/spdy/spdy_framer.cc b/net/spdy/spdy_framer.cc
index ebc523b06156981bd371077d1d3b2dd9d0332af4..f7b52831d7912d9bf166f3bbfb55f35d2559c948 100644
--- a/net/spdy/spdy_framer.cc
+++ b/net/spdy/spdy_framer.cc
@@ -305,13 +305,13 @@ size_t SpdyFramer::GetPushPromiseMinimumSize() const {
   return GetControlFrameHeaderSize() + 4;
 }
 
-size_t SpdyFramer::GetContinuationMinimumSize() const  {
+size_t SpdyFramer::GetContinuationMinimumSize() const {
   // Size, in bytes, of a CONTINUATION frame not including the variable-length
   // headers fragments.
   return GetControlFrameHeaderSize();
 }
 
-size_t SpdyFramer::GetAltSvcMinimumSize() const  {
+size_t SpdyFramer::GetAltSvcMinimumSize() const {
   // Size, in bytes, of an ALTSVC frame not including the Protocol-ID, Host, and
   // (optional) Origin fields, all of which can vary in length.
   // Note that this gives a lower bound on the frame size rather than a true
@@ -321,6 +321,12 @@ size_t SpdyFramer::GetAltSvcMinimumSize() const  {
   return GetControlFrameHeaderSize() + 9;
 }
 
+size_t SpdyFramer::GetPrioritySize() const {
+  // Size, in bytes, of a PRIORITY frame.
+  // Calculated as frame prefix + 4 (stream dependency) + 1 (weight)
+  return GetControlFrameHeaderSize() + 5;
+}
+
 size_t SpdyFramer::GetFrameMinimumSize() const {
   return std::min(GetDataFrameMinimumSize(), GetControlFrameHeaderSize());
 }
@@ -478,6 +484,8 @@ const char* SpdyFramer::FrameTypeToString(SpdyFrameType type) {
       return "CONTINUATION";
     case ALTSVC:
       return "ALTSVC";
+    case PRIORITY:
+      return "PRIORITY";
   }
   return "UNKNOWN_CONTROL_TYPE";
 }
@@ -969,6 +977,14 @@ void SpdyFramer::ProcessControlFrameHeader(uint16 control_frame_type_field) {
         set_error(SPDY_INVALID_CONTROL_FRAME_FLAGS);
       }
       break;
+    case PRIORITY:
+      if (current_frame_length_ != GetPrioritySize() ||
+          protocol_version() <= SPDY3) {
+        set_error(SPDY_INVALID_CONTROL_FRAME);
+      } else if (current_frame_flags_ != 0) {
+        set_error(SPDY_INVALID_CONTROL_FRAME_FLAGS);
+      }
+      break;
     default:
       LOG(WARNING) << "Valid " << display_protocol_
                    << " control frame with unhandled type: "
@@ -1748,6 +1764,13 @@ size_t SpdyFramer::ProcessControlFramePayload(const char* data, size_t len) {
           visitor_->OnBlocked(current_frame_stream_id_);
         }
         break;
+      case PRIORITY: {
+          DCHECK_LT(SPDY3, protocol_version());
+          // TODO(hkhalil): Process PRIORITY frames rather than ignore them.
+          reader.Seek(5);
+          DCHECK(reader.IsDoneReading());
+        }
+        break;
       default:
         // Unreachable.
         LOG(FATAL) << "Unhandled control frame " << current_frame_type_;