Use the Code's pointer offsets to find object references when disassembling IA32.

runtime/vm/disassembler_dbc.cc

Index: runtime/vm/disassembler_dbc.cc
diff --git a/runtime/vm/disassembler_dbc.cc b/runtime/vm/disassembler_dbc.cc
index 5c8b3a0038ac22f3bcc725068ebfe6e702caa9fe..a2095a0d80a5c02ea5eb3bf06414d0b77dfe6c73 100644
--- a/runtime/vm/disassembler_dbc.cc
+++ b/runtime/vm/disassembler_dbc.cc
@@ -10,6 +10,7 @@
 #include "platform/assert.h"
 #include "vm/constants_dbc.h"
 #include "vm/cpu.h"
+#include "vm/instructions.h"
 
 namespace dart {
 
@@ -214,6 +215,8 @@ void Disassembler::DecodeInstruction(char* hex_buffer,
                                      char* human_buffer,
                                      intptr_t human_size,
                                      int* out_instr_size,
+                                     const Code& code,
+                                     Object** object,
                                      uword pc) {
   const uint32_t instr = *reinterpret_cast<uint32_t*>(pc);
   const uint8_t opcode = instr & 0xFF;
@@ -229,6 +232,14 @@ void Disassembler::DecodeInstruction(char* hex_buffer,
   if (out_instr_size) {
     *out_instr_size = sizeof(uint32_t);
   }
+
+  *object = NULL;
+  if (!code.IsNull()) {
+    *object = &Object::Handle();
+    if (!DecodeLoadObjectFromPoolOrThread(pc, code, *object)) {
+      *object = NULL;
+    }
+  }
 }