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

extensions/common/extension_messages.cc

Index: extensions/common/extension_messages.cc
diff --git a/extensions/common/extension_messages.cc b/extensions/common/extension_messages.cc
index 15bc1210ad5743e42b14914c927422846e8fe040..47aa3275bdf6cadfb457fd30d583bd1e1df61aac 100644
--- a/extensions/common/extension_messages.cc
+++ b/extensions/common/extension_messages.cc
@@ -187,7 +187,7 @@ void ParamTraits<APIPermissionSet>::Write(
     Message* m, const param_type& p) {
   APIPermissionSet::const_iterator it = p.begin();
   const APIPermissionSet::const_iterator end = p.end();
-  WriteParam(m, p.size());
+  WriteParam(m, static_cast<uint32_t>(p.size()));
   for (; it != end; ++it) {
     WriteParam(m, it->id());
     it->Write(m);
@@ -197,7 +197,7 @@ void ParamTraits<APIPermissionSet>::Write(
 bool ParamTraits<APIPermissionSet>::Read(const Message* m,
                                          base::PickleIterator* iter,
                                          param_type* r) {
-  size_t size;
+  uint32_t size;
   if (!ReadParam(m, iter, &size))
     return false;
   for (size_t i = 0; i < size; ++i) {
@@ -225,7 +225,7 @@ void ParamTraits<ManifestPermissionSet>::Write(
     Message* m, const param_type& p) {
   ManifestPermissionSet::const_iterator it = p.begin();
   const ManifestPermissionSet::const_iterator end = p.end();
-  WriteParam(m, p.size());
+  WriteParam(m, static_cast<uint32_t>(p.size()));
   for (; it != end; ++it) {
     WriteParam(m, it->name());
     it->Write(m);
@@ -235,7 +235,7 @@ void ParamTraits<ManifestPermissionSet>::Write(
 bool ParamTraits<ManifestPermissionSet>::Read(const Message* m,
                                               base::PickleIterator* iter,
                                               param_type* r) {
-  size_t size;
+  uint32_t size;
   if (!ReadParam(m, iter, &size))
     return false;
   for (size_t i = 0; i < size; ++i) {