Support New isContentTypeSupported API

Adds support and tests for the new isContentTypeSupported API to the
Widevine DrmEngine.

Bug: 10244066

Merge of https://widevine-internal-review.googlesource.com/#/c/7321/
from the Widevine CDM repo.

Change-Id: I4f606de7897a49da745ff76faceeb358f8ac9073

libwvdrmengine/src/WVDrmFactory.cpp

@@ -23,6 +23,11 @@ bool WVDrmFactory::isCryptoSchemeSupported(const uint8_t uuid[16]) {
   return isWidevineUUID(uuid);
 }
 
+bool WVDrmFactory::isContentTypeSupported(const String8 &mimeType) {
+  // For now, only ISO-BMFF is supported, which has MIME-type video/mp4
+  return mimeType == "video/mp4";
+}
+
 status_t WVDrmFactory::createDrmPlugin(const uint8_t uuid[16],
                                           DrmPlugin** plugin) {
   if (!isCryptoSchemeSupported(uuid)) {