Moves manifest parsing to a new class, Reader.

mojo/shell/public/cpp/capabilities.h

Index: mojo/shell/public/cpp/capabilities.h
diff --git a/mojo/shell/public/cpp/capabilities.h b/mojo/shell/public/cpp/capabilities.h
index 39bc387f4adb123f96d11cd508bd214c8c4ef194..4ec4722ac31be400369f6f49d78946daabc3c40c 100644
--- a/mojo/shell/public/cpp/capabilities.h
+++ b/mojo/shell/public/cpp/capabilities.h
@@ -25,6 +25,7 @@ struct CapabilityRequest {
   CapabilityRequest();
   ~CapabilityRequest();
   bool operator==(const CapabilityRequest& other) const;
+  bool operator<(const CapabilityRequest& other) const;
   Classes classes;
   Interfaces interfaces;
 };
@@ -33,6 +34,7 @@ struct CapabilitySpec {
   CapabilitySpec();
   ~CapabilitySpec();
   bool operator==(const CapabilitySpec& other) const;
+  bool operator<(const CapabilitySpec& other) const;
   std::map<Class, Interfaces> provided;
   std::map<Name, CapabilityRequest> required;
 };