Remove Pickle::BeginWriteData/TrimWriteData, it's not used

base/pickle_unittest.cc

Index: base/pickle_unittest.cc
diff --git a/base/pickle_unittest.cc b/base/pickle_unittest.cc
index cc384c70617ae354ae31b8bc7a52c7c4cf9fce6e..dd00e6a5d4db4657ecf4f2f3bc363aea4dc6db82 100644
--- a/base/pickle_unittest.cc
+++ b/base/pickle_unittest.cc
@@ -58,10 +58,6 @@ void VerifyResult(const Pickle& pickle) {
   EXPECT_EQ(testdatalen, outdatalen);
   EXPECT_EQ(memcmp(testdata, outdata, outdatalen), 0);
 
-  EXPECT_TRUE(pickle.ReadData(&iter, &outdata, &outdatalen));
-  EXPECT_EQ(testdatalen, outdatalen);
-  EXPECT_EQ(memcmp(testdata, outdata, outdatalen), 0);
-
   // reads past the end should fail
   EXPECT_FALSE(pickle.ReadInt(&iter, &outint));
 }
@@ -79,14 +75,6 @@ TEST(PickleTest, EncodeDecode) {
   EXPECT_TRUE(pickle.WriteUInt16(testuint16));
   EXPECT_TRUE(pickle.WriteFloat(testfloat));
   EXPECT_TRUE(pickle.WriteData(testdata, testdatalen));
-
-  // Over allocate BeginWriteData so we can test TrimWriteData.
-  char* dest = pickle.BeginWriteData(testdatalen + 100);
-  EXPECT_TRUE(dest);
-  memcpy(dest, testdata, testdatalen);
-
-  pickle.TrimWriteData(testdatalen);
-
   VerifyResult(pickle);
 
   // test copy constructor