Reland "Add unprefixed EME tests for LoadSession()"

content/browser/media/encrypted_media_browsertest.cc

Index: content/browser/media/encrypted_media_browsertest.cc
diff --git a/content/browser/media/encrypted_media_browsertest.cc b/content/browser/media/encrypted_media_browsertest.cc
index 88c02f90e5568433a0c2c2f0c4cf8deaa2b48b0b..eafb2bf82fad4982ab350620c4a5d4a52ea434f3 100644
--- a/content/browser/media/encrypted_media_browsertest.cc
+++ b/content/browser/media/encrypted_media_browsertest.cc
@@ -83,6 +83,7 @@ class EncryptedMediaTest : public content::MediaBrowserTest,
     base::StringPairs query_params;
     query_params.push_back(std::make_pair("keySystem", CurrentKeySystem()));
     query_params.push_back(std::make_pair("runEncrypted", "1"));
+    query_params.push_back(std::make_pair("usePrefixedEME", "1"));
     RunMediaTestPage("mse_config_change.html", query_params, kEnded, true);
   }
 
@@ -107,6 +108,7 @@ class EncryptedMediaTest : public content::MediaBrowserTest,
     query_params.push_back(std::make_pair("keySystem", key_system));
     if (src_type == MSE)
       query_params.push_back(std::make_pair("useMSE", "1"));
+    query_params.push_back(std::make_pair("usePrefixedEME", "1"));
     RunMediaTestPage(html_page, query_params, expectation, true);
   }