Allow setting breakpoints in function literal field initializers under --dfe.

runtime/vm/debugger.cc

Index: runtime/vm/debugger.cc
diff --git a/runtime/vm/debugger.cc b/runtime/vm/debugger.cc
index ac05de0b61080fde02d7aebad73df7c4c1eaafbb..396a86974a67a5e334543a3a445ae54da0175e85 100644
--- a/runtime/vm/debugger.cc
+++ b/runtime/vm/debugger.cc
@@ -16,6 +16,7 @@
 #include "vm/flags.h"
 #include "vm/globals.h"
 #include "vm/json_stream.h"
+#include "vm/kernel_reader.h"
 #include "vm/longjump.h"
 #include "vm/message_handler.h"
 #include "vm/object.h"
@@ -57,6 +58,7 @@ DEFINE_FLAG(bool,
             "the VM service.");
 
 DECLARE_FLAG(bool, warn_on_pause_with_no_debugger);
+DECLARE_FLAG(bool, use_dart_frontend);
 
 #ifndef PRODUCT
 
@@ -2662,7 +2664,25 @@ bool Debugger::FindBestFit(const Script& script,
           // the breakpoint in.
           continue;
         }
-        if (Parser::FieldHasFunctionLiteralInitializer(field, &start, &end)) {
+        if (!field.has_initializer()) {
+          continue;
+        }
+
+        bool has_func_literal_initializer = false;
+#ifndef DART_PRECOMPILED_RUNTIME
+        if (FLAG_use_dart_frontend) {
+          has_func_literal_initializer =
+              kernel::KernelReader::FieldHasFunctionLiteralInitializer(
+                  field, &start, &end);
+        } else {
+#endif  // !DART_PRECOMPILED_RUNTIME
+          has_func_literal_initializer =
+              Parser::FieldHasFunctionLiteralInitializer(field, &start, &end);
+#ifndef DART_PRECOMPILED_RUNTIME
+        }
+#endif  // !DART_PRECOMPILED_RUNTIME

[siva, 2017/07/18 22:49:07]

Strictly speaking this entire function and most of other Debugger functionality
should not be included in DART_PRECOMPILED_RUNTIME, so maybe it is not necessary
to bracket this code here and instead look at excluding debugger stuff in
another CL.

[sivachandra, 2017/07/19 00:14:21]

Acknowledged.

+
+        if (has_func_literal_initializer) {
           if ((start <= token_pos && token_pos <= end) ||
               (token_pos <= start && start <= last_token_pos)) {
             return true;