Implement Chromium side of MediaKeys.isTypeSupported().

content/renderer/renderer_webkitplatformsupport_impl.cc

Index: content/renderer/renderer_webkitplatformsupport_impl.cc
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index 797285fc125d7174fbad4aca78548e04c28492f9..99e8a09caf0a4b88b5aa07dc378db2a34f3e82ef 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -832,6 +832,19 @@ RendererWebKitPlatformSupportImpl::signedPublicKeyAndChallengeString(
 
 //------------------------------------------------------------------------------
 
+blink::WebContentDecryptionModule::KeySystemSupportedResult
+RendererWebKitPlatformSupportImpl::isKeySystemSupported(
+    const WebString& key_system,
+    const WebString& init_data_type,
+    const WebString& container,
+    const WebString& codecs,
+    const WebString& capability) {
+  return WebContentDecryptionModuleImpl::IsKeySystemSupported(
+      key_system, init_data_type, container, codecs, capability);
+}
+
+//------------------------------------------------------------------------------
+
 void RendererWebKitPlatformSupportImpl::screenColorProfile(
     WebVector<char>* to_profile) {
 #if defined(OS_WIN)