Add CDM FileIO tests.

chrome/renderer/media/chrome_key_systems.cc

Index: chrome/renderer/media/chrome_key_systems.cc
diff --git a/chrome/renderer/media/chrome_key_systems.cc b/chrome/renderer/media/chrome_key_systems.cc
index 2b4ba6543f48271499b0175e283355c9ae92ba2e..bb59fae87ffb61dd955b4b8dcd812d3d603539ad 100644
--- a/chrome/renderer/media/chrome_key_systems.cc
+++ b/chrome/renderer/media/chrome_key_systems.cc
@@ -66,6 +66,8 @@ static void AddExternalClearKey(
       "org.chromium.externalclearkey";
   static const char kExternalClearKeyDecryptOnlyKeySystem[] =
       "org.chromium.externalclearkey.decryptonly";
+  static const char kExternalClearKeyFileIOTestKeySystem[] =
+      "org.chromium.externalclearkey.fileiotest";
   static const char kExternalClearKeyInitializeFailKeySystem[] =
       "org.chromium.externalclearkey.initializefail";
   static const char kExternalClearKeyPepperType[] =
@@ -91,15 +93,19 @@ static void AddExternalClearKey(
 
   concrete_key_systems->push_back(info);
 
+  // Add support of decrypt-only mode in ClearKeyCdm.
+  info.key_system = kExternalClearKeyDecryptOnlyKeySystem;
+  concrete_key_systems->push_back(info);
+
+  // A key system that triggers FileIO test in ClearKeyCdm.
+  info.key_system = kExternalClearKeyFileIOTestKeySystem;
+  concrete_key_systems->push_back(info);
+
   // A key system that Chrome thinks is supported by ClearKeyCdm, but actually
   // will be refused by ClearKeyCdm. This is to test the CDM initialization
   // failure case.
   info.key_system = kExternalClearKeyInitializeFailKeySystem;
   concrete_key_systems->push_back(info);
-
-  // Add support of decrypt-only mode in ClearKeyCdm.
-  info.key_system = kExternalClearKeyDecryptOnlyKeySystem;
-  concrete_key_systems->push_back(info);
 }
 #endif  // defined(ENABLE_PEPPER_CDMS)