- Support streaming of content without .wvm extension.

If the .wvm extension is not present, the file header
  is parsed to determine if it is Widevine content.
- Fixed a missing call to OpenSession.
- Fixed unit test build.
- Fixed x86-eng build.
- This is cherry-picked from master to hc-mr1 branch
  "DO NOT MERGE"
Change-Id: Ied0579325d3c11a91f6f182fe59cd978eca68368

proprietary/drmwvmplugin/include/WVDRMPluginAPI.h

@@ -43,6 +43,7 @@ class WVDRMPluginAPI {
 
     virtual void OpenSession() = 0;
     virtual void CloseSession() = 0;
+    virtual bool IsSupportedMediaType(const char *uri) = 0;
 
     virtual bool AcquireDrmInfo(std::string &assetPath, WVCredentials &credentials,
                                 std::string &dsPath,