Refactor WvCdmEventListener and some cleanups

Bug: 19771437

It is a merge of below CLs from Widevine CDM repo:

Clean up CdmSession and PolicyEngine testing injection
https://widevine-internal-review.googlesource.com/#/c/13700

Refactor WvCdmEventListener handling
https://widevine-internal-review.googlesource.com/#/c/13702

Change-Id: I356b90000c056113d394926862b859aab380d305

libwvdrmengine/cdm/core/include/policy_engine.h

@@ -7,6 +7,7 @@
 
 #include "license_protocol.pb.h"
 #include "max_res_engine.h"
+#include "scoped_ptr.h"
 #include "wv_cdm_types.h"
 
 namespace wvcdm {
@@ -15,7 +16,6 @@ using video_widevine_server::sdk::LicenseIdentification;
 
 class Clock;
 class CryptoSession;
-class PolicyEngineTest;
 
 // This acts as an oracle that basically says "Yes(true) you may still decrypt
 // or no(false) you may not decrypt this data anymore."
@@ -78,6 +78,8 @@ class PolicyEngine {
   bool IsLicenseForFuture() { return license_state_ == kLicenseStatePending; }
 
  private:
+  friend class PolicyEngineTest;
+
   typedef enum {
     kLicenseStateInitial,
     kLicenseStatePending,  // if license is issued for sometime in the future
@@ -87,8 +89,6 @@ class PolicyEngine {
     kLicenseStateExpired
   } LicenseState;
 
-  void Init(Clock* clock);
-
   int64_t GetLicenseDurationRemaining(int64_t current_time);
   int64_t GetPlaybackDurationRemaining(int64_t current_time);
 
@@ -98,6 +98,9 @@ class PolicyEngine {
 
   void UpdateRenewalRequest(int64_t current_time);
 
+  // These setters are for testing only. Takes ownership of the pointers.
+  void set_clock(Clock* clock);
+
   LicenseState license_state_;
   bool can_decrypt_;
 
@@ -124,11 +127,7 @@ class PolicyEngine {
   int64_t policy_max_duration_seconds_;
 
   MaxResEngine max_res_engine_;
-  Clock* clock_;
-
-  // For testing
-  friend class PolicyEngineTest;
-  PolicyEngine(CryptoSession* crypto_session, Clock* clock);
+  scoped_ptr<Clock> clock_;
 
   CORE_DISALLOW_COPY_AND_ASSIGN(PolicyEngine);
 };