Move MessageLocations constructor out of header

This is a bit unfortunate, but otherwise we would have to include
objects.h before message.h, since for the initialization of a Handle<T>,
the compiler checks that Object* can be assigned to T*. So it would
need to know about the inheritance for initializing Handle<Script> and
Handle<JSFunction>.

R=mstarzinger@chromium.org, titzer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1872373002

Cr-Commit-Position: refs/heads/master@{#35626}

src/messages.cc

@@ -12,6 +12,16 @@
 namespace v8 {
 namespace internal {
 
+MessageLocation::MessageLocation(Handle<Script> script, int start_pos,
+                                 int end_pos)
+    : script_(script), start_pos_(start_pos), end_pos_(end_pos) {}
+MessageLocation::MessageLocation(Handle<Script> script, int start_pos,
+                                 int end_pos, Handle<JSFunction> function)
+    : script_(script),
+      start_pos_(start_pos),
+      end_pos_(end_pos),
+      function_(function) {}
+MessageLocation::MessageLocation() : start_pos_(-1), end_pos_(-1) {}
 
 // If no message listeners have been registered this one is called
 // by default.

src/messages.h

@@ -24,13 +24,10 @@ class SourceInfo;
 
 class MessageLocation {
  public:
+  MessageLocation(Handle<Script> script, int start_pos, int end_pos);
   MessageLocation(Handle<Script> script, int start_pos, int end_pos,
-                  Handle<JSFunction> function = Handle<JSFunction>())
-      : script_(script),
-        start_pos_(start_pos),
-        end_pos_(end_pos),
-        function_(function) {}
-  MessageLocation() : start_pos_(-1), end_pos_(-1) { }
+                  Handle<JSFunction> function);
+  MessageLocation();
 
   Handle<Script> script() const { return script_; }
   int start_pos() const { return start_pos_; }