DO NOT MERGE Handle unlimited usage table capacity.

[ Merge of http://go/wvgerrit/103684 ]
[ Cherry pick of http://ag/12221244 ]

The OEMCrypto method for usage table capacity can return zero to
indicate that the usage table size is not explicitly limited.  The
CDM must handle this case with regard to the CDM's usage table
management and information querying.

The usage table initialization tests are extended to include cases
where the table does not have a defined limit.

AddEntry() was missing call to update the usage table header after
creating a new usage entry.  This call is now included and required
additional changes to the usage table unit tests.

Bug: 160560364
Test: Android unit tests
Change-Id: Ica5d181092d2938d24deba5005a211ca883cb0f0

libwvdrmengine/cdm/core/include/usage_table_header.h

@@ -93,6 +93,10 @@ class UsageTableHeader {
 
   size_t potential_table_capacity() const { return potential_table_capacity_; }
 
+  bool HasUnlimitedTableCapacity() const {
+    return potential_table_capacity_ == 0;
+  }
+
   // Returns the number of entries currently tracked by the CDM that
   // are related to usage info (streaming licenses).
   size_t UsageInfoCount() const;