SPDY: Fix flaky padding edge case.

net/spdy/spdy_framer_test.cc

Index: net/spdy/spdy_framer_test.cc
diff --git a/net/spdy/spdy_framer_test.cc b/net/spdy/spdy_framer_test.cc
index d33a7793bd4cc2995da1ea582e4b80687b38fa85..eee3cbcbdcb9ebad57341565ba9b32318bfeb26a 100644
--- a/net/spdy/spdy_framer_test.cc
+++ b/net/spdy/spdy_framer_test.cc
@@ -1647,6 +1647,47 @@ TEST_P(SpdyFramerTest, CreateDataFrame) {
   }
 
   {
+    const char kDescription[] =
+        "'hello' data frame with 1 byte padding, no FIN";
+    const unsigned char kV3FrameData[] = {  // Also applies for V2.
+      0x00, 0x00, 0x00, 0x01,
+      0x00, 0x00, 0x00, 0x05,
+      'h',  'e',  'l',  'l',
+      'o'
+    };
+
+    const unsigned char kV4FrameData[] = {
+      0x00, 0x06, 0x00, 0x10,      // Length = 6.  PAD_LOW set.
+      0x00, 0x00, 0x00, 0x01,
+      0x00,                        // Pad Low field.
+      'h',  'e',  'l',  'l',       // Data
+      'o',
+    };
+    const char bytes[] = "hello";
+
+    SpdyDataIR data_ir(1, StringPiece(bytes, strlen(bytes)));
+    // The pad low field itself is used for the 1-byte padding and no padding
+    // payload is needed.
+    data_ir.set_padding_len(1);
+    scoped_ptr<SpdyFrame> frame(framer.SerializeData(data_ir));
+    if (IsSpdy4()) {
+       CompareFrame(
+           kDescription, *frame, kV4FrameData, arraysize(kV4FrameData));
+    } else {
+       CompareFrame(
+           kDescription, *frame, kV3FrameData, arraysize(kV3FrameData));
+    }
+
+    frame.reset(framer.SerializeDataFrameHeaderWithPaddingLengthField(data_ir));
+    CompareCharArraysWithHexError(
+        kDescription,
+        reinterpret_cast<const unsigned char*>(frame->data()),
+        framer.GetDataFrameMinimumSize(),
+        IsSpdy4() ? kV4FrameData : kV3FrameData,
+        framer.GetDataFrameMinimumSize());
+  }
+
+  {
     const char kDescription[] = "Data frame with negative data byte, no FIN";
     const unsigned char kV3FrameData[] = {  // Also applies for V2.
       0x00, 0x00, 0x00, 0x01,