Type conversion fixes, gpu/ edition.

gpu/command_buffer/service/program_cache.cc

Index: gpu/command_buffer/service/program_cache.cc
diff --git a/gpu/command_buffer/service/program_cache.cc b/gpu/command_buffer/service/program_cache.cc
index ad395c7f4766d16a0ec9c93e0b1cb2c1ca1a6284..abdcfc0cb5db653fb3df311aea6ff5a43a73a855 100644
--- a/gpu/command_buffer/service/program_cache.cc
+++ b/gpu/command_buffer/service/program_cache.cc
@@ -123,9 +123,9 @@ void ProgramCache::ComputeProgramHash(
       current_pos += name_size;
       const GLint value = it->second;
       buffer[current_pos++] = value >> 24;
-      buffer[current_pos++] = value >> 16;
-      buffer[current_pos++] = value >> 8;
-      buffer[current_pos++] = value;
+      buffer[current_pos++] = static_cast<unsigned char>(value >> 16);
+      buffer[current_pos++] = static_cast<unsigned char>(value >> 8);
+      buffer[current_pos++] = static_cast<unsigned char>(value);
     }
   }
   base::SHA1HashBytes(buffer.get(),