Support column-based breakpoints in the VM and Observatory.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 1fcbdb078b7d49285b5c5bea5664e2b39b3a753b..032733222dddb4b474a3e2fce2f5f0d06566c3cb 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -8592,7 +8592,8 @@ void Script::SetLocationOffset(intptr_t line_offset,
 
 void Script::GetTokenLocation(intptr_t token_pos,
                               intptr_t* line,
-                              intptr_t* column) const {
+                              intptr_t* column,
+                              intptr_t* token_len) const {
   ASSERT(line != NULL);
   const TokenStream& tkns = TokenStream::Handle(tokens());
   if (column == NULL) {
@@ -8614,6 +8615,13 @@ void Script::GetTokenLocation(intptr_t token_pos,
     intptr_t relative_line = scanner.CurrentPosition().line;
     *line = relative_line + line_offset();
     *column = scanner.CurrentPosition().column;
+    if (token_len != NULL) {
+      if (scanner.current_token().literal != NULL) {
+        *token_len = scanner.current_token().literal->Length();
+      } else {
+        *token_len = 1;

[rmacnak, 2015/09/03 00:55:19]

Maybe otherwise keyword length?

[turnidge, 2015/09/04 18:05:29]

My hope was that the literal pointed to the keyword but perhaps this was wrong. 
(See scanner.cc:319)

+      }
+    }
     // On the first line of the script we must add the column offset.
     if (relative_line == 1) {
       *column += col_offset();