Improve Code object support in service and observatory

runtime/vm/disassembler.cc

Index: runtime/vm/disassembler.cc
diff --git a/runtime/vm/disassembler.cc b/runtime/vm/disassembler.cc
index 780318815df19fa57790b1cf36f2a78146a7cab0..044e1000247fbd6b2c144ac0d25272c2139fbc28 100644
--- a/runtime/vm/disassembler.cc
+++ b/runtime/vm/disassembler.cc
@@ -44,11 +44,13 @@ void DisassembleToJSONStream::ConsumeInstruction(char* hex_buffer,
                                                  intptr_t human_size,
                                                  uword pc) {
   uint8_t* pc_ptr = reinterpret_cast<uint8_t*>(pc);
-  JSONObject jsobj(&jsarr_);
-  jsobj.AddProperty("type", "DisassembledInstruction");
-  jsobj.AddPropertyF("pc", "%p", pc_ptr);
-  jsobj.AddProperty("hex", hex_buffer);
-  jsobj.AddProperty("human", human_buffer);
+  // Instructions are represented as three consecutive values in a JSON array.
+  // All three are strings. The first is the address of the instruction,
+  // the second is the hex string of the code, and the final is a human
+  // readable string.
+  jsarr_.AddValueF("%p", pc_ptr);
+  jsarr_.AddValue(hex_buffer);
+  jsarr_.AddValue(human_buffer);
 }
 
 
@@ -67,9 +69,12 @@ void DisassembleToJSONStream::Print(const char* format, ...) {
       p[i] = ' ';
     }
   }
-  JSONObject jsobj(&jsarr_);
-  jsobj.AddProperty("type", "DisassembledInstructionComment");
-  jsobj.AddProperty("comment", p);
+  // Instructions are represented as three consecutive values in a JSON array.
+  // All three are strings. Comments only use the third slot. See above comment
+  // for more information.
+  jsarr_.AddValue("");
+  jsarr_.AddValue("");
+  jsarr_.AddValue(p);
   free(p);
 }