Use MediaDrm property to ignore installed keybox

Merge from Widevine repo of http://go/wvgerrit/135984

If the MediaDrm property string debugIgnoreKeyboxCount is set to 1,
then the keybox will be ignored on the next initialization. This will
force an OTA keybox reprovisioning.

Equivalently, a 1 may be written to the file
L1/debug_ignore_keybox_count.txt.

In order to test a failed reprovisioning step, a value of 2 may be
used.

Bug: 187646550
Merged-In: Ie7d34a8b355398855f4ec43dd95dd73c5907bdeb
Change-Id: Ie7d34a8b355398855f4ec43dd95dd73c5907bdeb

libwvdrmengine/cdm/core/include/oemcrypto_adapter.h

@@ -16,6 +16,10 @@ namespace wvcdm {
 OEMCryptoResult OEMCrypto_InitializeAndCheckKeybox(
     bool* needs_keybox_provisioning);
 
+// This tells the OEMCrypto adapter to ignore the next |count| keyboxes and
+// report that it needs provisioning instead.
+OEMCryptoResult OEMCrypto_SetDebugIgnoreKeyboxCount(uint32_t count);
+
 // This attempts to open a session at the desired security level.
 // If one level is not available, the other will be used instead.
 OEMCryptoResult OEMCrypto_OpenSession(OEMCrypto_SESSION* session,