Make line-starts 32-bits TypedData instead of Array of smis.

runtime/vm/kernel_binary_flowgraph.cc

Index: runtime/vm/kernel_binary_flowgraph.cc
diff --git a/runtime/vm/kernel_binary_flowgraph.cc b/runtime/vm/kernel_binary_flowgraph.cc
index 9a30282c170922e5ceccc75b400cff73a4f4ad87..ec8a4983caee9e66bbf98d4e018f4abf1beb542a 100644
--- a/runtime/vm/kernel_binary_flowgraph.cc
+++ b/runtime/vm/kernel_binary_flowgraph.cc
@@ -7184,7 +7184,7 @@ String& StreamingFlowGraphBuilder::GetSourceFor(intptr_t index) {
   return String::Handle(String::null());
 }
 
-Array& StreamingFlowGraphBuilder::GetLineStartsFor(intptr_t index) {
+TypedData& StreamingFlowGraphBuilder::GetLineStartsFor(intptr_t index) {
   AlternativeReadingScope alt(reader_);
   SetOffset(reader_->size() - 4);
   intptr_t library_count = reader_->ReadUInt32();
@@ -7203,17 +7203,15 @@ Array& StreamingFlowGraphBuilder::GetLineStartsFor(intptr_t index) {
     SkipBytes(length);
     intptr_t line_count = ReadUInt();
     if (i == index) {
-      Array& array_object =
-          Array::Handle(Z, Array::New(line_count, Heap::kOld));
-      Smi& value = Smi::Handle(Z);
+      TypedData& line_starts = TypedData::Handle(
+          Z, TypedData::New(kTypedDataUint32ArrayCid, line_count, Heap::kOld));
       intptr_t previous_line_start = 0;
       for (intptr_t j = 0; j < line_count; ++j) {
         intptr_t line_start = ReadUInt() + previous_line_start;
-        value = Smi::New(line_start);
-        array_object.SetAt(j, value);
+        line_starts.SetUint32(j << 2, line_start);
         previous_line_start = line_start;
       }
-      return array_object;
+      return line_starts;
     } else {
       for (intptr_t j = 0; j < line_count; ++j) {
         ReadUInt();
@@ -7221,7 +7219,7 @@ Array& StreamingFlowGraphBuilder::GetLineStartsFor(intptr_t index) {
     }
   }
 
-  return Array::Handle(Array::null());
+  return TypedData::Handle(TypedData::null());
 }
 
 }  // namespace kernel