Remove methods only used in tests.

Remove HpackStringDecoder:StartOnly(), StartAndDecoderLength(), and
StartSpecialCaseShort().

This CL lands internal change 170871163 by bnc.

BUG=488484

Change-Id: I5ea3d3650980816d3bd0729a277d5786b5e5e974
Reviewed-on: https://chromium-review.googlesource.com/688714Reviewed-by: Helen Li <xunjieli@chromium.org>
Commit-Queue: Bence Béky <bnc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506802}

net/http2/hpack/decoder/hpack_string_decoder.h

@@ -32,11 +32,6 @@ namespace net {
 // Resume() when more input is available, repeating until kDecodeInProgress is
 // not returned. If kDecodeDone or kDecodeError is returned, then Resume() must
 // not be called until Start() has been called to start decoding a new string.
-//
-// There are 3 variants of Start in this class, participants in a performance
-// experiment. Perflab experiments show it is generally fastest to call
-// StartSpecialCaseShort rather than StartOnly (~9% slower) or
-// StartAndDecodeLength (~10% slower).
 class HTTP2_EXPORT_PRIVATE HpackStringDecoder {
  public:
   enum StringDecoderState {
@@ -45,31 +40,8 @@ class HTTP2_EXPORT_PRIVATE HpackStringDecoder {
     kResumeDecodingLength,
   };
 
-  // TODO(jamessynge): Get rid of all but one of the Start and Resume methods
-  // after all of the HPACK decoder is checked in and has been perf tested.
   template <class Listener>
   DecodeStatus Start(DecodeBuffer* db, Listener* cb) {
-    return StartSpecialCaseShort(db, cb);
-  }
-
-  template <class Listener>
-  DecodeStatus StartOnly(DecodeBuffer* db, Listener* cb) {
-    state_ = kStartDecodingLength;
-    return Resume(db, cb);
-  }
-
-  template <class Listener>
-  DecodeStatus StartAndDecodeLength(DecodeBuffer* db, Listener* cb) {
-    DecodeStatus status;
-    if (StartDecodingLength(db, cb, &status)) {
-      state_ = kDecodingString;
-      return DecodeString(db, cb);
-    }
-    return status;
-  }
-
-  template <class Listener>
-  DecodeStatus StartSpecialCaseShort(DecodeBuffer* db, Listener* cb) {
     // Fast decode path is used if the string is under 127 bytes and the
     // entire length of the string is in the decode buffer. More than 83% of
     // string lengths are encoded in just one byte.

net/http2/hpack/decoder/hpack_string_decoder_test.cc

@@ -25,35 +25,14 @@ const bool kMayReturnZeroOnFirst = false;
 const bool kCompressed = true;
 const bool kUncompressed = false;
 
-enum StartMethod {
-  kStart,
-  kStartOnly,
-  kStartAndDecodeLength,
-  kStartSpecialCaseShort,
-};
-
-class HpackStringDecoderTest
-    : public RandomDecoderTest,
-      public ::testing::WithParamInterface<StartMethod> {
+class HpackStringDecoderTest : public RandomDecoderTest {
  protected:
-  HpackStringDecoderTest()
-      : start_method_(GetParam()), listener_(&collector_) {}
+  HpackStringDecoderTest() : listener_(&collector_) {}
 
   DecodeStatus StartDecoding(DecodeBuffer* b) override {
     ++start_decoding_calls_;
     collector_.Clear();
-    switch (start_method_) {
-      case kStart:
-        return decoder_.Start(b, &listener_);
-      case kStartOnly:
-        return decoder_.StartOnly(b, &listener_);
-      case kStartAndDecodeLength:
-        return decoder_.StartAndDecodeLength(b, &listener_);
-      case kStartSpecialCaseShort:
-        return decoder_.StartSpecialCaseShort(b, &listener_);
-      default:
-        return DecodeStatus::kDecodeError;
-    }
+    return decoder_.Start(b, &listener_);
   }
 
   DecodeStatus ResumeDecoding(DecodeBuffer* b) override {
@@ -93,14 +72,13 @@ class HpackStringDecoderTest
         };
   }
 
-  const StartMethod start_method_;
   HpackStringDecoder decoder_;
   HpackStringCollector collector_;
   HpackStringDecoderVLoggingListener listener_;
   size_t start_decoding_calls_ = 0;
 };
 
-TEST_P(HpackStringDecoderTest, DecodeEmptyString) {
+TEST_F(HpackStringDecoderTest, DecodeEmptyString) {
   {
     Validator validator = ValidateDoneAndEmpty(MakeValidator("", kCompressed));
     const char kData[] = {0x80u};
@@ -121,7 +99,7 @@ TEST_P(HpackStringDecoderTest, DecodeEmptyString) {
   }
 }
 
-TEST_P(HpackStringDecoderTest, DecodeShortString) {
+TEST_F(HpackStringDecoderTest, DecodeShortString) {
   {
     // Make sure it stops after decoding the non-empty string.
     Validator validator =
@@ -141,7 +119,7 @@ TEST_P(HpackStringDecoderTest, DecodeShortString) {
   }
 }
 
-TEST_P(HpackStringDecoderTest, DecodeLongStrings) {
+TEST_F(HpackStringDecoderTest, DecodeLongStrings) {
   Http2String name = Random().RandString(1024);
   Http2String value = Random().RandString(65536);
   HpackBlockBuilder hbb;
@@ -173,13 +151,6 @@ TEST_P(HpackStringDecoderTest, DecodeLongStrings) {
   EXPECT_EQ(0u, b.Remaining());
 }
 
-INSTANTIATE_TEST_CASE_P(AllStartMethods,
-                        HpackStringDecoderTest,
-                        ::testing::Values(kStart,
-                                          kStartOnly,
-                                          kStartAndDecodeLength,
-                                          kStartSpecialCaseShort));
-
 }  // namespace
 }  // namespace test
 }  // namespace net