- Fix typos and add comments.

runtime/vm/coverage.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/coverage.h"
 
 #include "include/dart_api.h"
 
 #include "vm/compiler.h"
 #include "vm/isolate.h"
@@ skipping 57 matching lines @@
   int i = 0;
   while (i < functions.Length()) {
     HANDLESCOPE(isolate);
     function ^= functions.At(i);
     JSONObject jsobj(&jsarr);
     script = function.script();
     saved_url = script.url();
     jsobj.AddProperty("source", saved_url.ToCString());
     JSONArray hits_arr(&jsobj, "hits");
 
+    // We stay within this loop while we are seeing functions from the same
+    // source URI.
     while (i < functions.Length()) {
       function ^= functions.At(i);
       script = function.script();
       url = script.url();
       if (!url.Equals(saved_url)) {
         break;
       }
       CompileAndAdd(function, hits_arr);
       i++;
     }
   }
 
-  GrowableObjectArray& closures = GrowableObjectArray::Handle(
-      cls.closures());
+  GrowableObjectArray& closures =
+      GrowableObjectArray::Handle(cls.closures());
   if (!closures.IsNull()) {
     i = 0;
+    // We need to keep rechecking the length of the closures array, as handling
+    // a closure potentially adds new entries to the end.
     while (i < closures.Length()) {
       HANDLESCOPE(isolate);
       function ^= closures.At(i);
       JSONObject jsobj(&jsarr);
       script = function.script();
       saved_url = script.url();
       jsobj.AddProperty("source", saved_url.ToCString());
       JSONArray hits_arr(&jsobj, "hits");
 
+      // We stay within this loop while we are seeing functions from the same
+      // source URI.
       while (i < closures.Length()) {
         function ^= closures.At(i);
         script = function.script();
         url = script.url();
         if (!url.Equals(saved_url)) {
           break;
         }
         CompileAndAdd(function, hits_arr);
         i++;
       }
@@ skipping 45 matching lines @@
   void* file = (*file_open)(filename, true);
   if (file == NULL) {
     OS::Print("Failed to write coverage file: %s\n", filename);
     return;
   }
   (*file_write)(stream.buffer()->buf(), stream.buffer()->length(), file);
   (*file_close)(file);
 }
 
 }  // namespace dart