Fix GTS testL3PlayHDCPV* tests.

These tests verify whether a L3 device respects the HDCP policy set in the
license request. L3 device should only play the clear lead, and stop at
encrypted content. MeidaDrm should throw an ERROR_INSUFFICIENT_OUTPUT_PROTECTION
exception. This is because L3 device always returns current HDCP connection
status as HDCP_NONE.

This CL modifies the policy engine CanDecryptContent method to return
CdmResponseType instead of a boolean, so the app can generate the correct
error response if HDCP constriants are not met.

Test: GTS tests
  ANDROID_BUILD_TOP= ./android-gts/tooadefed run gts -m GtsMediaTestCases --test
  com.google.android.media.gts.WidevineDashPolicyTests#testL3PlayHDCPV*Required

Test: unit tests
  adb shell /data/app/policy_engine_unittest
  adb shell /data/app/policy_engine_constraints_unittest

Test: Play Movies

bug: 34258607
Change-Id: I11fc9da1e077e18e38f34159daae9d8ebcd948b6

libwvdrmengine/cdm/core/include/policy_engine.h

@@ -99,6 +99,10 @@ class PolicyEngine {
 
   bool CanRenew() { return policy_.can_renew(); }
 
+  bool IsSufficientOutputProtection(const KeyId& key_id) {
+    return license_keys_->MeetsConstraints(key_id);
+  }
+
  private:
   friend class PolicyEngineTest;
   friend class PolicyEngineConstraintsTest;