media: Enable encrypted media content browsertests when MojoCdm is used

media/cdm/default_cdm_factory.cc

Index: media/cdm/default_cdm_factory.cc
diff --git a/media/cdm/default_cdm_factory.cc b/media/cdm/default_cdm_factory.cc
index ab65df65815ea2c1ba114ab22f26c879faa8b5bc..6efa19c33195e6cbb4d674d04029af4b005eb4bc 100644
--- a/media/cdm/default_cdm_factory.cc
+++ b/media/cdm/default_cdm_factory.cc
@@ -9,7 +9,9 @@
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "media/base/key_system_names.h"
 #include "media/base/key_systems.h"
+#include "media/base/media_switches.h"
 #include "media/cdm/aes_decryptor.h"
 #include "url/gurl.h"
 
@@ -21,6 +23,16 @@ DefaultCdmFactory::DefaultCdmFactory() {
 DefaultCdmFactory::~DefaultCdmFactory() {
 }
 
+static bool ShouldCreateAesDecryptor(const std::string& key_system) {
+  if (CanUseAesDecryptor(key_system))
+    return true;
+
+  // Should create AesDecryptor to support External Clear Key key system.
+  // This is used for testing.
+  return base::FeatureList::IsEnabled(media::kExternalClearKeyForTesting) &&
+         IsExternalClearKey(key_system);
+}
+
 void DefaultCdmFactory::Create(
     const std::string& key_system,
     const GURL& security_origin,
@@ -35,7 +47,8 @@ void DefaultCdmFactory::Create(
         FROM_HERE, base::Bind(cdm_created_cb, nullptr, "Invalid origin."));
     return;
   }
-  if (!CanUseAesDecryptor(key_system)) {
+
+  if (!ShouldCreateAesDecryptor(key_system)) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::Bind(cdm_created_cb, nullptr, "Unsupported key system."));