Add message sizing to basic IPC traits and struct macros.

BUG=577685

Review URL: https://codereview.chromium.org/1655333002

Cr-Commit-Position: refs/heads/master@{#373720}

16 files changed, 584 insertions, 3 deletions

diff --git a/base/files/file_path.cc b/base/files/file_path.cc
index 5756dfc..fdaa46b 100644
--- a/base/files/file_path.cc
+++ b/base/files/file_path.cc
@@ -657,6 +657,14 @@ FilePath FilePath::FromUTF16Unsafe(const string16& utf16) {
 }
 #endif
 
+void FilePath::GetSizeForPickle(PickleSizer* sizer) const {
+#if defined(OS_WIN)
+  sizer->AddString16(path_);
+#else
+  sizer->AddString(path_);
+#endif
+}
+
 void FilePath::WriteToPickle(Pickle* pickle) const {
 #if defined(OS_WIN)
   pickle->WriteString16(path_);
diff --git a/base/files/file_path.h b/base/files/file_path.h
index 89e9cbf..4eb712a 100644
--- a/base/files/file_path.h
+++ b/base/files/file_path.h
@@ -138,6 +138,7 @@ namespace base {
 
 class Pickle;
 class PickleIterator;
+class PickleSizer;
 
 // An abstraction to isolate users from the differences between native
 // pathnames on different platforms.
@@ -377,6 +378,7 @@ class BASE_EXPORT FilePath {
   // Similar to FromUTF8Unsafe, but accepts UTF-16 instead.
   static FilePath FromUTF16Unsafe(const string16& utf16);
 
+  void GetSizeForPickle(PickleSizer* sizer) const;
   void WriteToPickle(Pickle* pickle) const;
   bool ReadFromPickle(PickleIterator* iter);
 
diff --git a/base/pickle.cc b/base/pickle.cc
index 8aa9f62..b12ec9a 100644
--- a/base/pickle.cc
+++ b/base/pickle.cc
@@ -208,6 +208,39 @@ bool PickleIterator::ReadBytes(const char** data, int length) {
   return true;
 }
 
+PickleSizer::PickleSizer() {}
+
+PickleSizer::~PickleSizer() {}
+
+void PickleSizer::AddString(const StringPiece& value) {
+  AddInt();
+  AddBytes(static_cast<int>(value.size()));
+}
+
+void PickleSizer::AddString16(const StringPiece16& value) {
+  AddInt();
+  AddBytes(static_cast<int>(value.size() * sizeof(char16)));
+}
+
+void PickleSizer::AddData(int length) {
+  CHECK_GE(length, 0);
+  AddInt();
+  AddBytes(length);
+}
+
+void PickleSizer::AddBytes(int length) {
+  payload_size_ += bits::Align(length, sizeof(uint32_t));
+}
+
+template <size_t length> void PickleSizer::AddBytesStatic() {
+  DCHECK_LE(length, static_cast<size_t>(std::numeric_limits<int>::max()));
+  AddBytes(length);
+}
+
+template void PickleSizer::AddBytesStatic<2>();
+template void PickleSizer::AddBytesStatic<4>();
+template void PickleSizer::AddBytesStatic<8>();
+
 Pickle::Attachment::Attachment() {}
 
 Pickle::Attachment::~Attachment() {}
diff --git a/base/pickle.h b/base/pickle.h
index e50fd68..18d8afe 100644
--- a/base/pickle.h
+++ b/base/pickle.h
@@ -109,6 +109,42 @@ class BASE_EXPORT PickleIterator {
   FRIEND_TEST_ALL_PREFIXES(PickleTest, GetReadPointerAndAdvance);
 };
 
+// This class provides an interface analogous to base::Pickle's WriteFoo()
+// methods and can be used to accurately compute the size of a hypothetical
+// Pickle's payload without having to reference the Pickle implementation.
+class BASE_EXPORT PickleSizer {
+ public:
+  PickleSizer();
+  ~PickleSizer();
+
+  // Returns the computed size of the payload.
+  size_t payload_size() const { return payload_size_; }
+
+  void AddBool() { return AddInt(); }
+  void AddInt() { AddPOD<int>(); }
+  void AddLongUsingDangerousNonPortableLessPersistableForm() { AddPOD<long>(); }
+  void AddUInt16() { return AddPOD<uint16_t>(); }
+  void AddUInt32() { return AddPOD<uint32_t>(); }
+  void AddInt64() { return AddPOD<int64_t>(); }
+  void AddUInt64() { return AddPOD<uint64_t>(); }
+  void AddSizeT() { return AddPOD<uint64_t>(); }
+  void AddFloat() { return AddPOD<float>(); }
+  void AddDouble() { return AddPOD<double>(); }
+  void AddString(const StringPiece& value);
+  void AddString16(const StringPiece16& value);
+  void AddData(int length);
+  void AddBytes(int length);
+
+ private:
+  // Just like AddBytes() but with a compile-time size for performance.
+  template<size_t length> void BASE_EXPORT AddBytesStatic();
+
+  template <typename T>
+  void AddPOD() { AddBytesStatic<sizeof(T)>(); }
+
+  size_t payload_size_ = 0;
+};
+
 // This class provides facilities for basic binary value packing and unpacking.
 //
 // The Pickle class supports appending primitive values (ints, strings, etc.)
diff --git a/base/pickle_unittest.cc b/base/pickle_unittest.cc
index b195a81..6dae177 100644
--- a/base/pickle_unittest.cc
+++ b/base/pickle_unittest.cc
@@ -575,4 +575,106 @@ TEST(PickleTest, ClaimBytes) {
   EXPECT_EQ(42, out_value);
 }
 
+// Checks that PickleSizer and Pickle agree on the size of things.
+TEST(PickleTest, PickleSizer) {
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteBool(true);
+    sizer.AddBool();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteInt(42);
+    sizer.AddInt();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteLongUsingDangerousNonPortableLessPersistableForm(42);
+    sizer.AddLongUsingDangerousNonPortableLessPersistableForm();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteUInt16(42);
+    sizer.AddUInt16();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteUInt32(42);
+    sizer.AddUInt32();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteInt64(42);
+    sizer.AddInt64();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteUInt64(42);
+    sizer.AddUInt64();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteSizeT(42);
+    sizer.AddSizeT();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteFloat(42.0f);
+    sizer.AddFloat();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteDouble(42.0);
+    sizer.AddDouble();
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteString(teststring);
+    sizer.AddString(teststring);
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteString16(teststring16);
+    sizer.AddString16(teststring16);
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteData(testdata, testdatalen);
+    sizer.AddData(testdatalen);
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+  {
+    TestingPickle pickle;
+    base::PickleSizer sizer;
+    pickle.WriteBytes(testdata, testdatalen);
+    sizer.AddBytes(testdatalen);
+    EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+  }
+}
+
 }  // namespace base
diff --git a/ipc/ipc_message_macros.h b/ipc/ipc_message_macros.h
index 7365b6c..9e9b3e0 100644
--- a/ipc/ipc_message_macros.h
+++ b/ipc/ipc_message_macros.h
@@ -45,6 +45,11 @@
 //     // Generate destructors.
 //     #include "ipc/struct_destructor_macros.h"
 //     #include "path/to/YYY_message_generator.h"
+//     // Generate param traits size methods.
+//     #include "ipc/param_traits_size_macros.h"
+//     namespace IPC {
+//     #include "path/to/YYY_message_generator.h"
+//     }  // namespace IPC
 //     // Generate param traits write methods.
 //     #include "ipc/param_traits_write_macros.h"
 //     namespace IPC {
diff --git a/ipc/ipc_message_utils.cc b/ipc/ipc_message_utils.cc
index 6c829c2..639cedd 100644
--- a/ipc/ipc_message_utils.cc
+++ b/ipc/ipc_message_utils.cc
@@ -72,6 +72,65 @@ bool ReadValue(const base::Pickle* m,
                base::Value** value,
                int recursion);
 
+void GetValueSize(base::PickleSizer* sizer,
+                  const base::Value* value,
+                  int recursion) {
+  if (recursion > kMaxRecursionDepth) {
+    LOG(WARNING) << "Max recursion depth hit in GetValueSize.";
+    return;
+  }
+
+  sizer->AddInt();
+  switch (value->GetType()) {
+    case base::Value::TYPE_NULL:
+      break;
+    case base::Value::TYPE_BOOLEAN:
+      sizer->AddBool();
+      break;
+    case base::Value::TYPE_INTEGER:
+      sizer->AddInt();
+      break;
+    case base::Value::TYPE_DOUBLE:
+      sizer->AddDouble();
+      break;
+    case base::Value::TYPE_STRING: {
+      const base::StringValue* result;
+      value->GetAsString(&result);
+      DCHECK(result);
+      GetParamSize(sizer, result->GetString());
+      break;
+    }
+    case base::Value::TYPE_BINARY: {
+      const base::BinaryValue* binary =
+          static_cast<const base::BinaryValue*>(value);
+      sizer->AddData(static_cast<int>(binary->GetSize()));
+      break;
+    }
+    case base::Value::TYPE_DICTIONARY: {
+      sizer->AddInt();
+      const base::DictionaryValue* dict =
+          static_cast<const base::DictionaryValue*>(value);
+      for (base::DictionaryValue::Iterator it(*dict); !it.IsAtEnd();
+           it.Advance()) {
+        GetParamSize(sizer, it.key());
+        GetValueSize(sizer, &it.value(), recursion + 1);
+      }
+      break;
+    }
+    case base::Value::TYPE_LIST: {
+      sizer->AddInt();
+      const base::ListValue* list = static_cast<const base::ListValue*>(value);
+      for (base::ListValue::const_iterator it = list->begin();
+           it != list->end(); ++it) {
+        GetValueSize(sizer, *it, recursion + 1);
+      }
+      break;
+    }
+    default:
+      NOTREACHED() << "Invalid base::Value type.";
+  }
+}
+
 void WriteValue(base::Pickle* m, const base::Value* value, int recursion) {
   bool result;
   if (recursion > kMaxRecursionDepth) {
@@ -278,6 +337,11 @@ void ParamTraits<bool>::Log(const param_type& p, std::string* l) {
   l->append(p ? "true" : "false");
 }
 
+void ParamTraits<signed char>::GetSize(base::PickleSizer* sizer,
+                                       const param_type& p) {
+  sizer->AddBytes(sizeof(param_type));
+}
+
 void ParamTraits<signed char>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(&p, sizeof(param_type));
 }
@@ -296,6 +360,11 @@ void ParamTraits<signed char>::Log(const param_type& p, std::string* l) {
   l->append(base::IntToString(p));
 }
 
+void ParamTraits<unsigned char>::GetSize(base::PickleSizer* sizer,
+                                       const param_type& p) {
+  sizer->AddBytes(sizeof(param_type));
+}
+
 void ParamTraits<unsigned char>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(&p, sizeof(param_type));
 }
@@ -314,6 +383,11 @@ void ParamTraits<unsigned char>::Log(const param_type& p, std::string* l) {
   l->append(base::UintToString(p));
 }
 
+void ParamTraits<unsigned short>::GetSize(base::PickleSizer* sizer,
+                                          const param_type& p) {
+  sizer->AddBytes(sizeof(param_type));
+}
+
 void ParamTraits<unsigned short>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(&p, sizeof(param_type));
 }
@@ -360,6 +434,11 @@ void ParamTraits<float>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("%e", p));
 }
 
+void ParamTraits<double>::GetSize(base::PickleSizer* sizer,
+                                  const param_type& p) {
+  sizer->AddBytes(sizeof(param_type));
+}
+
 void ParamTraits<double>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(reinterpret_cast<const char*>(&p), sizeof(param_type));
 }
@@ -389,6 +468,11 @@ void ParamTraits<base::string16>::Log(const param_type& p, std::string* l) {
   l->append(base::UTF16ToUTF8(p));
 }
 
+void ParamTraits<std::vector<char>>::GetSize(base::PickleSizer* sizer,
+                                             const param_type& p) {
+  sizer->AddData(static_cast<int>(p.size()));
+}
+
 void ParamTraits<std::vector<char>>::Write(base::Pickle* m,
                                            const param_type& p) {
   if (p.empty()) {
@@ -415,6 +499,11 @@ void ParamTraits<std::vector<char> >::Log(const param_type& p, std::string* l) {
   LogBytes(p, l);
 }
 
+void ParamTraits<std::vector<unsigned char>>::GetSize(base::PickleSizer* sizer,
+                                                      const param_type& p) {
+  sizer->AddData(static_cast<int>(p.size()));
+}
+
 void ParamTraits<std::vector<unsigned char>>::Write(base::Pickle* m,
                                                     const param_type& p) {
   if (p.empty()) {
@@ -443,6 +532,13 @@ void ParamTraits<std::vector<unsigned char> >::Log(const param_type& p,
   LogBytes(p, l);
 }
 
+void ParamTraits<std::vector<bool>>::GetSize(base::PickleSizer* sizer,
+                                             const param_type& p) {
+  GetParamSize(sizer, static_cast<int>(p.size()));
+  for (size_t i = 0; i < p.size(); ++i)
+    GetParamSize(sizer, static_cast<bool>(p[i]));
+}
+
 void ParamTraits<std::vector<bool>>::Write(base::Pickle* m,
                                            const param_type& p) {
   WriteParam(m, static_cast<int>(p.size()));
@@ -500,6 +596,11 @@ void ParamTraits<BrokerableAttachment::AttachmentId>::Log(const param_type& p,
   l->append(base::HexEncode(p.nonce, BrokerableAttachment::kNonceSize));
 }
 
+void ParamTraits<base::DictionaryValue>::GetSize(base::PickleSizer* sizer,
+                                                 const param_type& p) {
+  GetValueSize(sizer, &p, 0);
+}
+
 void ParamTraits<base::DictionaryValue>::Write(base::Pickle* m,
                                                const param_type& p) {
   WriteValue(m, &p, 0);
@@ -712,6 +813,11 @@ void ParamTraits<base::SharedMemoryHandle>::Log(const param_type& p,
 }
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 
+void ParamTraits<base::FilePath>::GetSize(base::PickleSizer* sizer,
+                                          const param_type& p) {
+  p.GetSizeForPickle(sizer);
+}
+
 void ParamTraits<base::FilePath>::Write(base::Pickle* m, const param_type& p) {
   p.WriteToPickle(m);
 }
@@ -726,6 +832,11 @@ void ParamTraits<base::FilePath>::Log(const param_type& p, std::string* l) {
   ParamTraits<base::FilePath::StringType>::Log(p.value(), l);
 }
 
+void ParamTraits<base::ListValue>::GetSize(base::PickleSizer* sizer,
+                                           const param_type& p) {
+  GetValueSize(sizer, &p, 0);
+}
+
 void ParamTraits<base::ListValue>::Write(base::Pickle* m, const param_type& p) {
   WriteValue(m, &p, 0);
 }
@@ -746,6 +857,12 @@ void ParamTraits<base::ListValue>::Log(const param_type& p, std::string* l) {
   l->append(json);
 }
 
+void ParamTraits<base::NullableString16>::GetSize(base::PickleSizer* sizer,
+                                                  const param_type& p) {
+  GetParamSize(sizer, p.string());
+  GetParamSize(sizer, p.is_null());
+}
+
 void ParamTraits<base::NullableString16>::Write(base::Pickle* m,
                                                 const param_type& p) {
   WriteParam(m, p.string());
@@ -774,6 +891,15 @@ void ParamTraits<base::NullableString16>::Log(const param_type& p,
   l->append(")");
 }
 
+void ParamTraits<base::File::Info>::GetSize(base::PickleSizer* sizer,
+                                            const param_type& p) {
+  GetParamSize(sizer, p.size);
+  GetParamSize(sizer, p.is_directory);
+  GetParamSize(sizer, p.last_modified.ToDoubleT());
+  GetParamSize(sizer, p.last_accessed.ToDoubleT());
+  GetParamSize(sizer, p.creation_time.ToDoubleT());
+}
+
 void ParamTraits<base::File::Info>::Write(base::Pickle* m,
                                           const param_type& p) {
   WriteParam(m, p.size);
@@ -814,6 +940,11 @@ void ParamTraits<base::File::Info>::Log(const param_type& p,
   l->append(")");
 }
 
+void ParamTraits<base::Time>::GetSize(base::PickleSizer* sizer,
+                                      const param_type& p) {
+  sizer->AddInt64();
+}
+
 void ParamTraits<base::Time>::Write(base::Pickle* m, const param_type& p) {
   ParamTraits<int64_t>::Write(m, p.ToInternalValue());
 }
@@ -832,6 +963,11 @@ void ParamTraits<base::Time>::Log(const param_type& p, std::string* l) {
   ParamTraits<int64_t>::Log(p.ToInternalValue(), l);
 }
 
+void ParamTraits<base::TimeDelta>::GetSize(base::PickleSizer* sizer,
+                                           const param_type& p) {
+  sizer->AddInt64();
+}
+
 void ParamTraits<base::TimeDelta>::Write(base::Pickle* m, const param_type& p) {
   ParamTraits<int64_t>::Write(m, p.ToInternalValue());
 }
@@ -851,6 +987,11 @@ void ParamTraits<base::TimeDelta>::Log(const param_type& p, std::string* l) {
   ParamTraits<int64_t>::Log(p.ToInternalValue(), l);
 }
 
+void ParamTraits<base::TimeTicks>::GetSize(base::PickleSizer* sizer,
+                                           const param_type& p) {
+  sizer->AddInt64();
+}
+
 void ParamTraits<base::TimeTicks>::Write(base::Pickle* m, const param_type& p) {
   ParamTraits<int64_t>::Write(m, p.ToInternalValue());
 }
@@ -902,6 +1043,19 @@ void ParamTraits<IPC::ChannelHandle>::Log(const param_type& p,
   l->append(")");
 }
 
+void ParamTraits<LogData>::GetSize(base::PickleSizer* sizer,
+                                   const param_type& p) {
+  GetParamSize(sizer, p.channel);
+  GetParamSize(sizer, p.routing_id);
+  GetParamSize(sizer, p.type);
+  GetParamSize(sizer, p.flags);
+  GetParamSize(sizer, p.sent);
+  GetParamSize(sizer, p.receive);
+  GetParamSize(sizer, p.dispatch);
+  GetParamSize(sizer, p.message_name);
+  GetParamSize(sizer, p.params);
+}
+
 void ParamTraits<LogData>::Write(base::Pickle* m, const param_type& p) {
   WriteParam(m, p.channel);
   WriteParam(m, p.routing_id);
@@ -979,6 +1133,11 @@ void ParamTraits<Message>::Log(const Message& p, std::string* l) {
 }
 
 #if defined(OS_WIN)
+void ParamTraits<HANDLE>::GetSize(base::PickleSizer* sizer,
+                                  const param_type& p) {
+  sizer->AddInt();
+}
+
 // Note that HWNDs/HANDLE/HCURSOR/HACCEL etc are always 32 bits, even on 64
 // bit systems. That's why we use the Windows macros to convert to 32 bits.
 void ParamTraits<HANDLE>::Write(base::Pickle* m, const param_type& p) {
@@ -999,6 +1158,11 @@ void ParamTraits<HANDLE>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("0x%p", p));
 }
 
+void ParamTraits<LOGFONT>::GetSize(base::PickleSizer* sizer,
+                                   const param_type& p) {
+  sizer->AddData(sizeof(LOGFONT));
+}
+
 void ParamTraits<LOGFONT>::Write(base::Pickle* m, const param_type& p) {
   m->WriteData(reinterpret_cast<const char*>(&p), sizeof(LOGFONT));
 }
@@ -1024,6 +1188,10 @@ void ParamTraits<LOGFONT>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("<LOGFONT>"));
 }
 
+void ParamTraits<MSG>::GetSize(base::PickleSizer* sizer, const param_type& p) {
+  sizer->AddData(sizeof(MSG));
+}
+
 void ParamTraits<MSG>::Write(base::Pickle* m, const param_type& p) {
   m->WriteData(reinterpret_cast<const char*>(&p), sizeof(MSG));
 }
diff --git a/ipc/ipc_message_utils.h b/ipc/ipc_message_utils.h
index 5654e75..d8b6607 100644
--- a/ipc/ipc_message_utils.h
+++ b/ipc/ipc_message_utils.h
@@ -100,6 +100,12 @@ struct NoParams {
 };
 
 template <class P>
+static inline void GetParamSize(base::PickleSizer* sizer, const P& p) {
+  typedef typename SimilarTypeTraits<P>::Type Type;
+  ParamTraits<Type>::GetSize(sizer, static_cast<const Type&>(p));
+}
+
+template <class P>
 static inline void WriteParam(base::Pickle* m, const P& p) {
   typedef typename SimilarTypeTraits<P>::Type Type;
   ParamTraits<Type>::Write(m, static_cast<const Type& >(p));
@@ -124,6 +130,9 @@ static inline void LogParam(const P& p, std::string* l) {
 template <>
 struct ParamTraits<bool> {
   typedef bool param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddBool();
+  }
   static void Write(base::Pickle* m, const param_type& p) { m->WriteBool(p); }
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -136,6 +145,7 @@ struct ParamTraits<bool> {
 template <>
 struct IPC_EXPORT ParamTraits<signed char> {
   typedef signed char param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -146,6 +156,7 @@ struct IPC_EXPORT ParamTraits<signed char> {
 template <>
 struct IPC_EXPORT ParamTraits<unsigned char> {
   typedef unsigned char param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -156,6 +167,7 @@ struct IPC_EXPORT ParamTraits<unsigned char> {
 template <>
 struct IPC_EXPORT ParamTraits<unsigned short> {
   typedef unsigned short param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -166,6 +178,9 @@ struct IPC_EXPORT ParamTraits<unsigned short> {
 template <>
 struct ParamTraits<int> {
   typedef int param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddInt();
+  }
   static void Write(base::Pickle* m, const param_type& p) { m->WriteInt(p); }
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -178,6 +193,9 @@ struct ParamTraits<int> {
 template <>
 struct ParamTraits<unsigned int> {
   typedef unsigned int param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddInt();
+  }
   static void Write(base::Pickle* m, const param_type& p) { m->WriteInt(p); }
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -190,6 +208,9 @@ struct ParamTraits<unsigned int> {
 template <>
 struct ParamTraits<long> {
   typedef long param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddLongUsingDangerousNonPortableLessPersistableForm();
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     m->WriteLongUsingDangerousNonPortableLessPersistableForm(p);
   }
@@ -204,6 +225,9 @@ struct ParamTraits<long> {
 template <>
 struct ParamTraits<unsigned long> {
   typedef unsigned long param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddLongUsingDangerousNonPortableLessPersistableForm();
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     m->WriteLongUsingDangerousNonPortableLessPersistableForm(p);
   }
@@ -218,6 +242,9 @@ struct ParamTraits<unsigned long> {
 template <>
 struct ParamTraits<long long> {
   typedef long long param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddInt64();
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     m->WriteInt64(static_cast<int64_t>(p));
   }
@@ -232,6 +259,9 @@ struct ParamTraits<long long> {
 template <>
 struct ParamTraits<unsigned long long> {
   typedef unsigned long long param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddInt64();
+  }
   static void Write(base::Pickle* m, const param_type& p) { m->WriteInt64(p); }
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -247,6 +277,9 @@ struct ParamTraits<unsigned long long> {
 template <>
 struct IPC_EXPORT ParamTraits<float> {
   typedef float param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddFloat();
+  }
   static void Write(base::Pickle* m, const param_type& p) { m->WriteFloat(p); }
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -259,6 +292,7 @@ struct IPC_EXPORT ParamTraits<float> {
 template <>
 struct IPC_EXPORT ParamTraits<double> {
   typedef double param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -271,6 +305,9 @@ struct IPC_EXPORT ParamTraits<double> {
 template <>
 struct ParamTraits<std::string> {
   typedef std::string param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddString(p);
+  }
   static void Write(base::Pickle* m, const param_type& p) { m->WriteString(p); }
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -283,6 +320,9 @@ struct ParamTraits<std::string> {
 template <>
 struct ParamTraits<base::string16> {
   typedef base::string16 param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    sizer->AddString16(p);
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     m->WriteString16(p);
   }
@@ -297,6 +337,7 @@ struct ParamTraits<base::string16> {
 template <>
 struct IPC_EXPORT ParamTraits<std::vector<char> > {
   typedef std::vector<char> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle*,
                    base::PickleIterator* iter,
@@ -307,6 +348,7 @@ struct IPC_EXPORT ParamTraits<std::vector<char> > {
 template <>
 struct IPC_EXPORT ParamTraits<std::vector<unsigned char> > {
   typedef std::vector<unsigned char> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -317,6 +359,7 @@ struct IPC_EXPORT ParamTraits<std::vector<unsigned char> > {
 template <>
 struct IPC_EXPORT ParamTraits<std::vector<bool> > {
   typedef std::vector<bool> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -327,6 +370,11 @@ struct IPC_EXPORT ParamTraits<std::vector<bool> > {
 template <class P>
 struct ParamTraits<std::vector<P> > {
   typedef std::vector<P> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, static_cast<int>(p.size()));
+    for (size_t i = 0; i < p.size(); i++)
+      GetParamSize(sizer, p[i]);
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, static_cast<int>(p.size()));
     for (size_t i = 0; i < p.size(); i++)
@@ -361,6 +409,12 @@ struct ParamTraits<std::vector<P> > {
 template <class P>
 struct ParamTraits<std::set<P> > {
   typedef std::set<P> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, static_cast<int>(p.size()));
+    typename param_type::const_iterator iter;
+    for (iter = p.begin(); iter != p.end(); ++iter)
+      GetParamSize(sizer, *iter);
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, static_cast<int>(p.size()));
     typename param_type::const_iterator iter;
@@ -389,6 +443,14 @@ struct ParamTraits<std::set<P> > {
 template <class K, class V, class C, class A>
 struct ParamTraits<std::map<K, V, C, A> > {
   typedef std::map<K, V, C, A> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, static_cast<int>(p.size()));
+    typename param_type::const_iterator iter;
+    for (iter = p.begin(); iter != p.end(); ++iter) {
+      GetParamSize(sizer, iter->first);
+      GetParamSize(sizer, iter->second);
+    }
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, static_cast<int>(p.size()));
     typename param_type::const_iterator iter;
@@ -421,6 +483,10 @@ struct ParamTraits<std::map<K, V, C, A> > {
 template <class A, class B>
 struct ParamTraits<std::pair<A, B> > {
   typedef std::pair<A, B> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, p.first);
+    GetParamSize(sizer, p.second);
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, p.first);
     WriteParam(m, p.second);
@@ -455,6 +521,7 @@ struct IPC_EXPORT ParamTraits<BrokerableAttachment::AttachmentId> {
 template <>
 struct IPC_EXPORT ParamTraits<base::DictionaryValue> {
   typedef base::DictionaryValue param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -504,6 +571,7 @@ struct IPC_EXPORT ParamTraits<base::SharedMemoryHandle> {
 template <>
 struct IPC_EXPORT ParamTraits<base::FilePath> {
   typedef base::FilePath param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -514,6 +582,7 @@ struct IPC_EXPORT ParamTraits<base::FilePath> {
 template <>
 struct IPC_EXPORT ParamTraits<base::ListValue> {
   typedef base::ListValue param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -524,6 +593,7 @@ struct IPC_EXPORT ParamTraits<base::ListValue> {
 template <>
 struct IPC_EXPORT ParamTraits<base::NullableString16> {
   typedef base::NullableString16 param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -534,6 +604,7 @@ struct IPC_EXPORT ParamTraits<base::NullableString16> {
 template <>
 struct IPC_EXPORT ParamTraits<base::File::Info> {
   typedef base::File::Info param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -556,6 +627,7 @@ struct SimilarTypeTraits<HWND> {
 template <>
 struct IPC_EXPORT ParamTraits<base::Time> {
   typedef base::Time param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -566,6 +638,7 @@ struct IPC_EXPORT ParamTraits<base::Time> {
 template <>
 struct IPC_EXPORT ParamTraits<base::TimeDelta> {
   typedef base::TimeDelta param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -576,6 +649,7 @@ struct IPC_EXPORT ParamTraits<base::TimeDelta> {
 template <>
 struct IPC_EXPORT ParamTraits<base::TimeTicks> {
   typedef base::TimeTicks param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -586,6 +660,7 @@ struct IPC_EXPORT ParamTraits<base::TimeTicks> {
 template <>
 struct ParamTraits<base::Tuple<>> {
   typedef base::Tuple<> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {}
   static void Write(base::Pickle* m, const param_type& p) {}
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -599,6 +674,9 @@ struct ParamTraits<base::Tuple<>> {
 template <class A>
 struct ParamTraits<base::Tuple<A>> {
   typedef base::Tuple<A> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, base::get<0>(p));
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, base::get<0>(p));
   }
@@ -615,6 +693,10 @@ struct ParamTraits<base::Tuple<A>> {
 template <class A, class B>
 struct ParamTraits<base::Tuple<A, B>> {
   typedef base::Tuple<A, B> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, base::get<0>(p));
+    GetParamSize(sizer, base::get<1>(p));
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, base::get<0>(p));
     WriteParam(m, base::get<1>(p));
@@ -635,6 +717,11 @@ struct ParamTraits<base::Tuple<A, B>> {
 template <class A, class B, class C>
 struct ParamTraits<base::Tuple<A, B, C>> {
   typedef base::Tuple<A, B, C> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, base::get<0>(p));
+    GetParamSize(sizer, base::get<1>(p));
+    GetParamSize(sizer, base::get<2>(p));
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, base::get<0>(p));
     WriteParam(m, base::get<1>(p));
@@ -659,6 +746,12 @@ struct ParamTraits<base::Tuple<A, B, C>> {
 template <class A, class B, class C, class D>
 struct ParamTraits<base::Tuple<A, B, C, D>> {
   typedef base::Tuple<A, B, C, D> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, base::get<0>(p));
+    GetParamSize(sizer, base::get<1>(p));
+    GetParamSize(sizer, base::get<2>(p));
+    GetParamSize(sizer, base::get<3>(p));
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, base::get<0>(p));
     WriteParam(m, base::get<1>(p));
@@ -687,6 +780,13 @@ struct ParamTraits<base::Tuple<A, B, C, D>> {
 template <class A, class B, class C, class D, class E>
 struct ParamTraits<base::Tuple<A, B, C, D, E>> {
   typedef base::Tuple<A, B, C, D, E> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, base::get<0>(p));
+    GetParamSize(sizer, base::get<1>(p));
+    GetParamSize(sizer, base::get<2>(p));
+    GetParamSize(sizer, base::get<3>(p));
+    GetParamSize(sizer, base::get<4>(p));
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, base::get<0>(p));
     WriteParam(m, base::get<1>(p));
@@ -752,6 +852,11 @@ struct ParamTraits<ScopedVector<P> > {
 template <class P, size_t stack_capacity>
 struct ParamTraits<base::StackVector<P, stack_capacity> > {
   typedef base::StackVector<P, stack_capacity> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, static_cast<int>(p->size()));
+    for (size_t i = 0; i < p->size(); i++)
+      GetParamSize(sizer, p[i]);
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, static_cast<int>(p->size()));
     for (size_t i = 0; i < p->size(); i++)
@@ -792,6 +897,14 @@ struct ParamTraits<base::SmallMap<NormalMap, kArraySize, EqualKey, MapInit> > {
   typedef base::SmallMap<NormalMap, kArraySize, EqualKey, MapInit> param_type;
   typedef typename param_type::key_type K;
   typedef typename param_type::data_type V;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    GetParamSize(sizer, static_cast<int>(p.size()));
+    typename param_type::const_iterator iter;
+    for (iter = p.begin(); iter != p.end(); ++iter) {
+      GetParamSize(sizer, iter->first);
+      GetParamSize(sizer, iter->second);
+    }
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     WriteParam(m, static_cast<int>(p.size()));
     typename param_type::const_iterator iter;
@@ -824,6 +937,12 @@ struct ParamTraits<base::SmallMap<NormalMap, kArraySize, EqualKey, MapInit> > {
 template <class P>
 struct ParamTraits<scoped_ptr<P> > {
   typedef scoped_ptr<P> param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p) {
+    bool valid = !!p;
+    GetParamSize(sizer, valid);
+    if (valid)
+      GetParamSize(sizer, *p);
+  }
   static void Write(base::Pickle* m, const param_type& p) {
     bool valid = !!p;
     WriteParam(m, valid);
@@ -875,6 +994,7 @@ struct IPC_EXPORT ParamTraits<IPC::ChannelHandle> {
 template <>
 struct IPC_EXPORT ParamTraits<LogData> {
   typedef LogData param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -897,6 +1017,7 @@ struct IPC_EXPORT ParamTraits<Message> {
 template <>
 struct IPC_EXPORT ParamTraits<HANDLE> {
   typedef HANDLE param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -907,6 +1028,7 @@ struct IPC_EXPORT ParamTraits<HANDLE> {
 template <>
 struct IPC_EXPORT ParamTraits<LOGFONT> {
   typedef LOGFONT param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -917,6 +1039,7 @@ struct IPC_EXPORT ParamTraits<LOGFONT> {
 template <>
 struct IPC_EXPORT ParamTraits<MSG> {
   typedef MSG param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
diff --git a/ipc/ipc_message_utils_unittest.cc b/ipc/ipc_message_utils_unittest.cc
index f3aa31a..0c9a7da 100644
--- a/ipc/ipc_message_utils_unittest.cc
+++ b/ipc/ipc_message_utils_unittest.cc
@@ -90,5 +90,31 @@ TEST(IPCMessageUtilsTest, StackVector) {
     EXPECT_EQ(stack_vector[i], output[i]);
 }
 
+// Tests that PickleSizer and Pickle agree on the size of a complex base::Value.
+TEST(IPCMessageUtilsTest, ValueSize) {
+  scoped_ptr<base::DictionaryValue> value(new base::DictionaryValue);
+  value->SetWithoutPathExpansion("foo", new base::FundamentalValue(42));
+  value->SetWithoutPathExpansion("bar", new base::FundamentalValue(3.14));
+  value->SetWithoutPathExpansion("baz", new base::StringValue("hello"));
+  value->SetWithoutPathExpansion("qux", base::Value::CreateNullValue());
+
+  scoped_ptr<base::DictionaryValue> nested_dict(new base::DictionaryValue);
+  nested_dict->SetWithoutPathExpansion("foobar", new base::FundamentalValue(5));
+  value->SetWithoutPathExpansion("nested", std::move(nested_dict));
+
+  scoped_ptr<base::ListValue> list_value(new base::ListValue);
+  list_value->Append(new base::StringValue("im a string"));
+  list_value->Append(new base::StringValue("im another string"));
+  value->SetWithoutPathExpansion("awesome-list", std::move(list_value));
+
+  base::Pickle pickle;
+  IPC::WriteParam(&pickle, *value);
+
+  base::PickleSizer sizer;
+  IPC::GetParamSize(&sizer, *value);
+
+  EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+}
+
 }  // namespace
 }  // namespace IPC
diff --git a/ipc/param_traits_macros.h b/ipc/param_traits_macros.h
index 7c4cc692..1003440 100644
--- a/ipc/param_traits_macros.h
+++ b/ipc/param_traits_macros.h
@@ -13,6 +13,8 @@
   template <>                                                \
   struct IPC_MESSAGE_EXPORT ParamTraits<struct_name> {       \
     typedef struct_name param_type;                          \
+    static void GetSize(base::PickleSizer* sizer,            \
+                        const param_type& p);                \
     static void Write(base::Pickle* m, const param_type& p); \
     static bool Read(const base::Pickle* m,                  \
                      base::PickleIterator* iter,             \
@@ -53,6 +55,8 @@
   template <>                                                      \
   struct IPC_MESSAGE_EXPORT ParamTraits<enum_name> {               \
     typedef enum_name param_type;                                  \
+    static void GetSize(base::PickleSizer* sizer,                  \
+                        const param_type& p);                      \
     static void Write(base::Pickle* m, const param_type& p);       \
     static bool Read(const base::Pickle* m,                        \
                      base::PickleIterator* iter,                   \
diff --git a/ipc/param_traits_size_macros.h b/ipc/param_traits_size_macros.h
new file mode 100644
index 0000000..142b55a
--- /dev/null
+++ b/ipc/param_traits_size_macros.h
@@ -0,0 +1,40 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IPC_PARAM_TRAITS_SIZE_MACROS_H_
+#define IPC_PARAM_TRAITS_SIZE_MACROS_H_
+
+// Null out all the macros that need nulling.
+#include "ipc/ipc_message_null_macros.h"
+
+// STRUCT declarations cause corresponding STRUCT_TRAITS declarations to occur.
+#undef IPC_STRUCT_BEGIN_WITH_PARENT
+#undef IPC_STRUCT_MEMBER
+#undef IPC_STRUCT_END
+#define IPC_STRUCT_BEGIN_WITH_PARENT(struct_name, parent) \
+  IPC_STRUCT_TRAITS_BEGIN(struct_name)
+#define IPC_STRUCT_MEMBER(type, name, ...) IPC_STRUCT_TRAITS_MEMBER(name)
+#define IPC_STRUCT_END() IPC_STRUCT_TRAITS_END()
+
+// Set up so next include will generate size methods.
+#undef IPC_STRUCT_TRAITS_BEGIN
+#undef IPC_STRUCT_TRAITS_MEMBER
+#undef IPC_STRUCT_TRAITS_PARENT
+#undef IPC_STRUCT_TRAITS_END
+#define IPC_STRUCT_TRAITS_BEGIN(struct_name) \
+  void ParamTraits<struct_name>::GetSize(base::PickleSizer* sizer, \
+                                         const param_type& p) {
+#define IPC_STRUCT_TRAITS_MEMBER(name) GetParamSize(sizer, p.name);
+#define IPC_STRUCT_TRAITS_PARENT(type) ParamTraits<type>::GetSize(sizer, p);
+#define IPC_STRUCT_TRAITS_END() }
+
+#undef IPC_ENUM_TRAITS_VALIDATE
+#define IPC_ENUM_TRAITS_VALIDATE(enum_name, validation_expression) \
+  void ParamTraits<enum_name>::GetSize(base::PickleSizer* sizer,   \
+                                       const param_type& value) {  \
+    sizer->AddInt();                                               \
+  }
+
+#endif  // IPC_PARAM_TRAITS_SIZE_MACROS_H_
+
diff --git a/mojo/public/cpp/bindings/lib/native_serialization.h b/mojo/public/cpp/bindings/lib/native_serialization.h
index 3c2e54e..d2f9088 100644
--- a/mojo/public/cpp/bindings/lib/native_serialization.h
+++ b/mojo/public/cpp/bindings/lib/native_serialization.h
@@ -29,7 +29,9 @@ struct ShouldUseNativeSerializer { static const bool value = false; };
 
 template <typename T>
 size_t GetSerializedSizeNative_(const T& value) {
-  return IPC::ParamTraits<T>::GetSize(value);
+  base::PickleSizer sizer;
+  IPC::ParamTraits<T>::GetSize(&sizer, value);
+  return sizer.payload_size() + sizeof(ArrayHeader);
 }
 
 template <typename T>
@@ -46,8 +48,24 @@ void SerializeNative_(const T& value,
   base::Pickle* pickle = pickler->pickle();
   const char* data_start = pickle->end_of_payload();
 
+#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
+  const char* payload_base = pickle->payload();
+  size_t size_before_write = pickle->payload_size();
+#endif
+
   IPC::ParamTraits<T>::Write(pickle, value);
 
+#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
+  // Ensure the pickle buffer hasn't moved.
+  DCHECK_EQ(payload_base, pickle->payload());
+  // Explicitly validate that the value returned by GetSize() always equals the
+  // number of bytes actually written by Write().
+  DCHECK_GE(pickle->payload_size(), size_before_write);
+  size_t bytes_written = pickle->payload_size() - size_before_write;
+  DCHECK_EQ(bytes_written + sizeof(ArrayHeader),
+            GetSerializedSizeNative_(value));
+#endif
+
   // Fix up the ArrayHeader so that num_elements contains the length of the
   // pickled data.
   size_t pickled_size = pickle->end_of_payload() - data_start;
diff --git a/mojo/public/cpp/bindings/tests/pickled_struct_blink.cc b/mojo/public/cpp/bindings/tests/pickled_struct_blink.cc
index 602f15ae..57a1915 100644
--- a/mojo/public/cpp/bindings/tests/pickled_struct_blink.cc
+++ b/mojo/public/cpp/bindings/tests/pickled_struct_blink.cc
@@ -25,6 +25,13 @@ PickledStructBlink::~PickledStructBlink() {}
 
 namespace IPC {
 
+void ParamTraits<mojo::test::PickledStructBlink>::GetSize(
+    base::PickleSizer* sizer,
+    const param_type& p) {
+  sizer->AddInt();
+  sizer->AddInt();
+}
+
 void ParamTraits<mojo::test::PickledStructBlink>::Write(base::Pickle* m,
                                                         const param_type& p) {
   m->WriteInt(p.foo());
diff --git a/mojo/public/cpp/bindings/tests/pickled_struct_blink.h b/mojo/public/cpp/bindings/tests/pickled_struct_blink.h
index c4406b4..ce5b364 100644
--- a/mojo/public/cpp/bindings/tests/pickled_struct_blink.h
+++ b/mojo/public/cpp/bindings/tests/pickled_struct_blink.h
@@ -16,6 +16,7 @@
 namespace base {
 class Pickle;
 class PickleIterator;
+class PickleSizer;
 }
 
 namespace mojo {
@@ -61,7 +62,7 @@ template <>
 struct ParamTraits<mojo::test::PickledStructBlink> {
   using param_type = mojo::test::PickledStructBlink;
 
-  static size_t GetSize(const param_type& p) { return 8; }
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
diff --git a/mojo/public/cpp/bindings/tests/pickled_struct_chromium.cc b/mojo/public/cpp/bindings/tests/pickled_struct_chromium.cc
index d45a44a5..0dee03f 100644
--- a/mojo/public/cpp/bindings/tests/pickled_struct_chromium.cc
+++ b/mojo/public/cpp/bindings/tests/pickled_struct_chromium.cc
@@ -22,6 +22,13 @@ PickledStructChromium::~PickledStructChromium() {}
 
 namespace IPC {
 
+void ParamTraits<mojo::test::PickledStructChromium>::GetSize(
+    base::PickleSizer* sizer,
+    const param_type& p) {
+  sizer->AddInt();
+  sizer->AddInt();
+}
+
 void ParamTraits<mojo::test::PickledStructChromium>::Write(
     base::Pickle* m,
     const param_type& p) {
diff --git a/mojo/public/cpp/bindings/tests/pickled_struct_chromium.h b/mojo/public/cpp/bindings/tests/pickled_struct_chromium.h
index b84f7b3..ec34572 100644
--- a/mojo/public/cpp/bindings/tests/pickled_struct_chromium.h
+++ b/mojo/public/cpp/bindings/tests/pickled_struct_chromium.h
@@ -15,6 +15,7 @@
 namespace base {
 class Pickle;
 class PickleIterator;
+class PickleSizer;
 }
 
 namespace mojo {
@@ -55,7 +56,7 @@ template <>
 struct ParamTraits<mojo::test::PickledStructChromium> {
   using param_type = mojo::test::PickledStructChromium;
 
-  static size_t GetSize(const param_type& p) { return 8; }
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,