Properly close plugins on SIGTERM and exit

test: adb reboot while playing netflix and check logcat
  to make sure session are closed.

[ Merge of http://go/wvgerrit/133063 ]

bug: 193099676
Change-Id: I375695673b0c366e09fb857f5ae7a9cb6b946779

libwvdrmengine/mediadrm/include_hidl/WVDrmPlugin.h

@@ -8,6 +8,7 @@
 #define WV_DRM_PLUGIN_H_
 
 #include <map>
+#include <list>
 
 #include "cdm_client_property_set.h"
 #include "cdm_identifier.h"
@@ -18,6 +19,7 @@
 #include "HidlTypes.h"
 #include "WVGenericCryptoInterface.h"
 #include "WVTypes.h"
+#include <utils/Mutex.h>
 
 namespace wvdrm {
 namespace hardware {
@@ -26,6 +28,7 @@ namespace V1_4 {
 namespace widevine {
 
 using std::map;
+using android::Mutex;
 using wvcdm::CdmIdentifier;
 using wvcdm::CdmKeyStatusMap;
 using wvcdm::CdmSessionId;
@@ -45,6 +48,8 @@ struct WVDrmPlugin : public ::drm::V1_4::IDrmPlugin, IDrmPluginListener,
 
   virtual ~WVDrmPlugin();
 
+  void Close();
+
   Return<void> openSession(openSession_cb _hidl_cb) override;
 
   Return<void> openSession_1_1(SecurityLevel securityLevel, openSession_1_1_cb _hidl_cb) override;
@@ -450,6 +455,47 @@ struct WVDrmPlugin : public ::drm::V1_4::IDrmPlugin, IDrmPluginListener,
     uint32_t getNextUniqueId();
   } mCdmIdentifierBuilder;
 
+  // Properly close plugins on SIGTERM then exit
+  class Terminator {
+   public:
+    static void Register(WVDrmPlugin* plugin) { instance().DoRegister(plugin); }
+    static void Forget(WVDrmPlugin* plugin) { instance().DoForget(plugin); }
+    static void Terminate(int /*signal*/) { instance().DoTerminate(); }
+
+   private:
+    WVDRM_DISALLOW_COPY_AND_ASSIGN(Terminator);
+
+    Terminator() {
+      signal(SIGTERM, Terminate);
+    }
+
+    static Terminator& instance() {
+      static Terminator instance;
+      return instance;
+    }
+
+    void DoRegister(WVDrmPlugin* plugin) {
+      Mutex::Autolock lock(mLock);
+      mPlugins.push_back(plugin);
+    }
+
+    void DoForget(WVDrmPlugin* plugin) {
+      Mutex::Autolock lock(mLock);
+      mPlugins.remove(plugin);
+    }
+
+    void DoTerminate() {
+      Mutex::Autolock lock(mLock);
+      for_each(mPlugins.begin(), mPlugins.end(), [] (WVDrmPlugin* plugin) {
+        plugin->Close();
+      });
+      exit(0);
+    }
+
+    std::list<WVDrmPlugin*> mPlugins;
+    Mutex mLock;
+  };
+
   sp<wvcdm::WvContentDecryptionModule> const mCDM;
   WVGenericCryptoInterface* mCrypto;
   map<CdmSessionId, CryptoSession> mCryptoSessions;

libwvdrmengine/mediadrm/src_hidl/WVDrmPlugin.cpp

@@ -196,10 +196,17 @@ WVDrmPlugin::WVDrmPlugin(const sp<WvContentDecryptionModule>& cdm,
     mCDM(cdm),
     mCrypto(crypto),
     mCryptoSessions(),
-    mAppPackageName(appPackageName) {}
+    mAppPackageName(appPackageName) {
+  Terminator::Register(this);
+}
 
 WVDrmPlugin::~WVDrmPlugin() {
   wvcdm::SetLoggingUid(mCdmIdentifierBuilder.user_id());
+  Terminator::Forget(this);
+  Close();
+}
+
+void WVDrmPlugin::Close() {
   typedef map<CdmSessionId, CryptoSession>::iterator mapIterator;
   for (mapIterator iter = mCryptoSessions.begin();
        iter != mCryptoSessions.end();