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/include/WVDrmFactory.h

@@ -19,6 +19,8 @@ class WVDrmFactory : public android::DrmFactory {
 
   virtual bool isCryptoSchemeSupported(const uint8_t uuid[16]);
 
+  virtual bool isContentTypeSupported(const android::String8 &mimeType);
+
   virtual android::status_t createDrmPlugin(const uint8_t uuid[16],
                                             android::DrmPlugin** plugin);