Add compile time checks against longs being used in IPC structs on 32 bit Android.

base/pickle.cc

Index: base/pickle.cc
diff --git a/base/pickle.cc b/base/pickle.cc
index b12ec9a53e8f31e6c8443fba51e5139392f41ee5..ba78c4ba33bb2d3b319b150fdef42d504c138996 100644
--- a/base/pickle.cc
+++ b/base/pickle.cc
@@ -11,6 +11,7 @@
 
 #include "base/bits.h"
 #include "base/macros.h"
+#include "base/numerics/safe_conversions.h"
 #include "build/build_config.h"
 
 namespace base {
@@ -84,12 +85,20 @@ bool PickleIterator::ReadBool(bool* result) {
   return ReadBuiltinType(result);
 }
 
-bool PickleIterator::ReadInt(int* result) {
+bool PickleIterator::ReadInt(int* result) {
   return ReadBuiltinType(result);
 }
 
 bool PickleIterator::ReadLong(long* result) {
-  return ReadBuiltinType(result);
+  // Always read long as a 64-bit value to ensure compatibility between 32-bit
+  // and 64-bit processes.
+  int64_t result_int64 = 0;
+  if (!ReadBuiltinType(&result_int64))
+    return false;
+  // CHECK if the cast truncates the value so that we know to change this IPC
+  // parameter to use int64_t.
+  *result = base::checked_cast<long>(result_int64);
+  return true;
 }
 
 bool PickleIterator::ReadUInt16(uint16_t* result) {
@@ -108,16 +117,6 @@ bool PickleIterator::ReadUInt64(uint64_t* result) {
   return ReadBuiltinType(result);
 }
 
-bool PickleIterator::ReadSizeT(size_t* result) {
-  // Always read size_t as a 64-bit value to ensure compatibility between 32-bit
-  // and 64-bit processes.
-  uint64_t result_uint64 = 0;
-  bool success = ReadBuiltinType(&result_uint64);
-  *result = static_cast<size_t>(result_uint64);
-  // Fail if the cast above truncates the value.
-  return success && (*result == result_uint64);
-}
-
 bool PickleIterator::ReadFloat(float* result) {
   // crbug.com/315213
   // The source data may not be properly aligned, and unaligned float reads