Pass DecryptConfig parameters over IPC and use it in AVDA.

media/base/decrypt_config.h

Index: media/base/decrypt_config.h
diff --git a/media/base/decrypt_config.h b/media/base/decrypt_config.h
index febd0fe866968a244379ef2d875656426970e06c..553b3004928d44af191e8646785ea06da1b4d593 100644
--- a/media/base/decrypt_config.h
+++ b/media/base/decrypt_config.h
@@ -5,6 +5,7 @@
 #ifndef MEDIA_BASE_DECRYPT_CONFIG_H_
 #define MEDIA_BASE_DECRYPT_CONFIG_H_
 
+#include <ostream>
 #include <string>
 #include <vector>
 
@@ -56,6 +57,9 @@ class MEDIA_EXPORT DecryptConfig {
   // Returns true if all fields in |config| match this config.
   bool Matches(const DecryptConfig& config) const;
 
+  // Prints to std::ostream.
+  std::ostream& Print(std::ostream& os) const;
+
  private:
   const std::string key_id_;
 
@@ -71,4 +75,9 @@ class MEDIA_EXPORT DecryptConfig {
 
 }  // namespace media
 
+inline std::ostream& operator<<(std::ostream& os,

[xhwang, 2015/10/22 06:13:51]

We don't like to overload operators, even for logging if not absolutely
necessary.

https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Operator_Ove...

Can we just have a AsHumanReadableString() function that returns a string? It
won't be super efficient, but since it's only for logging in debug builds I
think it's fine...

[Tima Vaisburd, 2015/10/22 17:15:45]

May I ask why? In my humble and maybe uninformed opinion operator<<() is
superior and it is also a well-known idiom. And it is for logging only, anyway?

[xhwang, 2015/10/22 18:11:25]

I searched around and do see some use of operator<< for logging. So this should
be fine. I think something like ToString() is used more often but I respect your
choice here :)

+                                const media::DecryptConfig& obj) {
+  return obj.Print(os);
+}
+
 #endif  // MEDIA_BASE_DECRYPT_CONFIG_H_