Verify MediaKeys parameter values consistently

Source/modules/encryptedmedia/MediaKeys.cpp

Index: Source/modules/encryptedmedia/MediaKeys.cpp
diff --git a/Source/modules/encryptedmedia/MediaKeys.cpp b/Source/modules/encryptedmedia/MediaKeys.cpp
index d0e173a96c1859077feaaf9cfdbc00005c6e1bb6..b3c213e922e2c3cbd080609ace217d0d5b5f6974 100644
--- a/Source/modules/encryptedmedia/MediaKeys.cpp
+++ b/Source/modules/encryptedmedia/MediaKeys.cpp
@@ -53,7 +53,7 @@ PassRefPtrWillBeRawPtr<MediaKeys> MediaKeys::create(ExecutionContext* context, c
     }
 
     // 2. If keySystem is not one of the user agent's supported Key Systems, throw a NotSupportedError and abort these steps.
-    if (!ContentDecryptionModule::supportsKeySystem(keySystem)) {
+    if (!isKeySystemSupported(keySystem)) {
         exceptionState.throwDOMException(NotSupportedError, "The '" + keySystem + "' key system is not supported.");
         return nullptr;
     }
@@ -108,7 +108,7 @@ PassRefPtrWillBeRawPtr<MediaKeySession> MediaKeys::createSession(ExecutionContex
 
     // 1. If type contains a MIME type that is not supported or is not supported by the keySystem,
     // throw a NOT_SUPPORTED_ERR exception and abort these steps.
-    if (!m_cdm->supportsMIMEType(contentType)) {
+    if (!isKeySystemSupportedWithContentType(m_keySystem, contentType)) {
         exceptionState.throwDOMException(NotSupportedError, "The type provided ('" + contentType + "') is unsupported.");
         return nullptr;
     }
@@ -141,7 +141,7 @@ bool MediaKeys::isTypeSupported(const String& keySystem, const String& contentTy
 
     // 2. If keySystem contains an unrecognized or unsupported Key System, return false and abort
     // these steps. Key system string comparison is case-sensitive.
-    if (!MIMETypeRegistry::isSupportedEncryptedMediaMIMEType(keySystem, "", ""))
+    if (!isKeySystemSupported(keySystem))
         return false;
 
     // 3. If contentType is null or an empty string, return true and abort these steps.
@@ -150,9 +150,22 @@ bool MediaKeys::isTypeSupported(const String& keySystem, const String& contentTy
 
     // 4. If the Key System specified by keySystem does not support decrypting the container and/or
     // codec specified by contentType, return false and abort these steps.
+    return isKeySystemSupportedWithContentType(keySystem, contentType);
+}
+
+bool MediaKeys::isKeySystemSupported(const String& keySystem)
+{
+    ASSERT(!keySystem.isEmpty());
+    return MIMETypeRegistry::isSupportedEncryptedMediaMIMEType(keySystem, "", "");
+}
+
+bool MediaKeys::isKeySystemSupportedWithContentType(const String& keySystem, const String& contentType)
+{
+    ASSERT(!keySystem.isEmpty());
+    ASSERT(!contentType.isEmpty());

[acolwell GONE FROM CHROMIUM, 2014/02/28 16:50:40]

nit: I'm not sure there is a lot of value having 2 methods here. I actually find
it a little confusing especially since these both ultimately bottom out in the
same MIMETypeRegistry call. Also the fact that there are parameter checks before
these methods are even called make the ASSERTS() here seem redundant.

[jrummell, 2014/02/28 19:06:52]

Done.

+
     ContentType type(contentType);
     String codecs = type.parameter("codecs");
-
     return MIMETypeRegistry::isSupportedEncryptedMediaMIMEType(keySystem, type.type(), codecs);
 }