Use schemas bundled in extensions to convert policies loaded on Windows.

components/policy/core/common/schema.h

Index: components/policy/core/common/schema.h
diff --git a/components/policy/core/common/schema.h b/components/policy/core/common/schema.h
index 91dc850087617be85cd1b0fcc23acba4a22f80f1..dcc78284eb246145726c7c50e93d869404360c06 100644
--- a/components/policy/core/common/schema.h
+++ b/components/policy/core/common/schema.h
@@ -51,6 +51,16 @@ class POLICY_EXPORT Schema {
   // is returned and |error| contains a reason for the failure.
   static Schema Parse(const std::string& schema, std::string* error);
 
+  // Same as Parse(), but if |with_backwards_compatibility| is true then arrays
+  // that don't declare a schema for their items will default to be arrays of
+  // strings. This is meant to support Legacy Browser Support until it is
+  // updated to use a proper schema.

[Mattias Nissler (ping if slow), 2013/12/03 20:22:00]

I don't get why LBS needs this - shouldn't arrays that don't declare their item
type just use the natural type we pull from the registry (which is  string for
string-typed registry keys?). What am I missing? Would be could to clarify the
comment to elaborate on why exactly LBS needs this.

[Joao da Silva, 2013/12/04 10:20:06]

LBS does not include the "items" schema because otherwise it would exceed the
maximum size of registry values in ADM templates. Without this workaround,
Schema::InternalStorage::ParseList would break because it requires an "items"
subschema for "type"="array" schemas.

The main question is whether we should be strict and require "complete" schemas,
or be more lax and let whatever doesn't match the schema just stay as is found
by the loaders.

I opted for the strict approach, so that the GUI builder for CPanel and similar
tools have complete information and the expected types. This also forces authors
to completely define the policies' format. LBS will be updated during the
M34-stable weeks to declare a complete schema too, and then this code will be
removed.

If you agree then I'll clarify this comment and leave the code as is. WDYT?

+  // TODO(joaodasilva): remove this by M35. http://crbug.com/325349
+  static Schema ParseWithBackwardsCompatibility(
+      const std::string& schema,
+      std::string* error,
+      bool with_backwards_compatibility);
+
   // Returns true if this Schema is valid. Schemas returned by the methods below
   // may be invalid, and in those cases the other methods must not be used.
   bool valid() const { return node_ != NULL; }