Extensions: Clarify ManifestHandler interface expectations.

extensions/common/manifest_handler.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_COMMON_MANIFEST_HANDLER_H_
 #define EXTENSIONS_COMMON_MANIFEST_HANDLER_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 11 matching lines @@
 // An interface for clients that recognize and parse keys in extension
 // manifests.
 class ManifestHandler {
  public:
   ManifestHandler();
   virtual ~ManifestHandler();
 
   // Attempts to parse the extension's manifest.
   // Returns true on success or false on failure; if false, |error| will
   // be set to a failure message.
+  // This should not do any IO.

[lazyboy, 2017/04/26 22:06:53]

nit:
// This does not require any IO operations.

[karandeepb, 2017/04/26 22:20:00]

Done. I was directing comments to the "implementors" of the interface.

   virtual bool Parse(Extension* extension, base::string16* error) = 0;
 
   // Validate that files associated with this manifest key exist.
   // Validation takes place after parsing. May also append a series of
-  // warning messages to |warnings|.
+  // warning messages to |warnings|. It is guaranteed that this is called on a

[lazyboy, 2017/04/26 22:06:53]

nit: It is not guaranteed, but the caller should guarantee that.
// This may require IO operations.
should be enough to give the hint.

[karandeepb, 2017/04/26 22:20:00]

Done.

+  // thread which can make IO calls.
   //
   // Otherwise, returns false, and a description of the error is
   // returned in |error|.
   // TODO(yoz): Change error to base::string16. See crbug.com/71980.
   virtual bool Validate(const Extension* extension,
                         std::string* error,
                         std::vector<InstallWarning>* warnings) const;
 
   // If false (the default), only parse the manifest if a registered
   // key is present in the manifest. If true, always attempt to parse
@@ skipping 117 matching lines @@
   // The priority for each manifest handler. Handlers with lower priority
   // values are evaluated first.
   ManifestHandlerPriorityMap priority_map_;
 
   bool is_finalized_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_MANIFEST_HANDLER_H_