Remove unused IPC::Message priority.

base/pickle.cc

Index: base/pickle.cc
diff --git a/base/pickle.cc b/base/pickle.cc
index af3191b9d86db2785fe375ecbcb045cf0a420870..1d300b962d3a138563e33803073e5133f2bc3403 100644
--- a/base/pickle.cc
+++ b/base/pickle.cc
@@ -170,15 +170,15 @@ Pickle::Pickle(int header_size)
   header_->payload_size = 0;
 }
 
-Pickle::Pickle(const char* data, int data_len)
+Pickle::Pickle(const char* data, size_t data_len)
     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
       header_size_(0),
       capacity_(kCapacityReadOnly),
       variable_buffer_offset_(0) {
-  if (data_len >= static_cast<int>(sizeof(Header)))
+  if (data_len >= sizeof(Header))
     header_size_ = data_len - header_->payload_size;
 
-  if (header_size_ > static_cast<unsigned int>(data_len))
+  if (header_size_ > data_len)
     header_size_ = 0;
 
   if (header_size_ != AlignInt(header_size_, sizeof(uint32)))