Delta encode pc descriptors, and combine pc kind and try index into single field.

runtime/vm/raw_object.cc

Index: runtime/vm/raw_object.cc
diff --git a/runtime/vm/raw_object.cc b/runtime/vm/raw_object.cc
index 2d83e8f80994802238d5262a4c6b2b05fb52f16a..04378e71a9bef9fdda6a42bda2119b5fb7c44436 100644
--- a/runtime/vm/raw_object.cc
+++ b/runtime/vm/raw_object.cc
@@ -18,11 +18,6 @@ namespace dart {
 DEFINE_FLAG(bool, validate_overwrite, true, "Verify overwritten fields.");
 #endif  // DEBUG
 
-const intptr_t RawPcDescriptors::kFullRecSize =
-    sizeof(RawPcDescriptors::PcDescriptorRec);
-const intptr_t RawPcDescriptors::kCompressedRecSize =
-    sizeof(RawPcDescriptors::CompressedPcDescriptorRec);
-
 bool RawObject::IsVMHeapObject() const {
   return Dart::vm_isolate()->heap()->Contains(ToAddr(this));
 }
@@ -142,11 +137,8 @@ intptr_t RawObject::SizeFromClass() const {
     case kPcDescriptorsCid: {
       const RawPcDescriptors* raw_descriptors =
           reinterpret_cast<const RawPcDescriptors*>(this);
-      const intptr_t num_descriptors = raw_descriptors->ptr()->length_;
-      const intptr_t rec_size_in_bytes =
-          raw_descriptors->ptr()->record_size_in_bytes_;
-      instance_size = PcDescriptors::InstanceSize(num_descriptors,
-                                                  rec_size_in_bytes);
+      intptr_t length = raw_descriptors->ptr()->length_;
+      instance_size = PcDescriptors::InstanceSize(length);
       break;
     }
     case kStackmapCid: {
@@ -555,16 +547,9 @@ bool RawInstructions::ContainsPC(RawObject* raw_obj, uword pc) {
 }
 
 
-intptr_t RawPcDescriptors::RecordSize(bool has_try_index) {
-  return has_try_index ? RawPcDescriptors::kFullRecSize
-                       : RawPcDescriptors::kCompressedRecSize;
-}
-
-
 intptr_t RawPcDescriptors::VisitPcDescriptorsPointers(
     RawPcDescriptors* raw_obj, ObjectPointerVisitor* visitor) {
-  return PcDescriptors::InstanceSize(raw_obj->ptr()->length_,
-                                     raw_obj->ptr()->record_size_in_bytes_);
+  return PcDescriptors::InstanceSize(raw_obj->ptr()->length_);
 }