Implement padding for SPDY4/HTTP2 DATA frames.

net/spdy/spdy_protocol.h

Index: net/spdy/spdy_protocol.h
diff --git a/net/spdy/spdy_protocol.h b/net/spdy/spdy_protocol.h
index 095718d3444870b1f5acdc08eaec3200b14d927a..fd1351a487e48b3f8eb7f774689881325c7434a5 100644
--- a/net/spdy/spdy_protocol.h
+++ b/net/spdy/spdy_protocol.h
@@ -291,8 +291,11 @@ enum SpdyFrameType {
 
 // Flags on data packets.
 enum SpdyDataFlags {
-  DATA_FLAG_NONE = 0,
-  DATA_FLAG_FIN = 1,
+DATA_FLAG_NONE = 0x00,
+  DATA_FLAG_FIN = 0x01,
+  DATA_FLAG_END_SEGMENT = 0x02,
+  DATA_FLAG_PAD_LOW = 0x10,
+  DATA_FLAG_PAD_HIGH = 0x20
 };
 
 // Flags on control packets
@@ -483,6 +486,29 @@ class NET_EXPORT_PRIVATE SpdyDataIR
 
   base::StringPiece data() const { return data_; }
 
+  bool pad_low() const { return pad_low_; }
+
+  bool pad_high() const { return pad_high_; }
+
+  int padding_payload_len() const { return padding_payload_len_; }
+
+  void set_padding_len(int padding_len) {
+    // The padding_len should be in (0, 65535 + 2].
+    // Note that SpdyFramer::GetDataFrameMaximumPayload() enforces the overall
+    // payload size later so we actually can't pad more than 16375 bytes.
+    DCHECK_GT(padding_len, 0);
+    DCHECK_LT(padding_len, 65537);
+
+    if (padding_len <= 256) {
+      pad_low_ = true;
+      --padding_len;
+    } else {
+      pad_low_ = pad_high_ = true;
+      padding_len -= 2;
+    }
+    padding_payload_len_ = padding_len;
+  }
+
   // Deep-copy of data (keep private copy).
   void SetDataDeep(const base::StringPiece& data) {
     data_store_.reset(new std::string(data.data(), data.length()));
@@ -502,6 +528,11 @@ class NET_EXPORT_PRIVATE SpdyDataIR
   scoped_ptr<std::string> data_store_;
   base::StringPiece data_;
 
+  bool pad_low_;
+  bool pad_high_;
+  // padding_payload_len_ = desired padding length - len(padding length field).
+  int padding_payload_len_;
+
   DISALLOW_COPY_AND_ASSIGN(SpdyDataIR);
 };