Ref count Timer implementation

[ Merge of http://go/wvgerrit/78763 ]

The android timer instance is held by a regular pointer rather
than reference counted as all classes that derive from RefBase
should be. This could result in a double deallocation, if the
timer is ever passed to a strong pointer.

Bug: 79364026
Test: WV unit/integration tests. GtsMediaTestCases. Play movies
      playback tests.

Change-Id: I01f622bc045e1012f2240b3775a6d121f9415463

libwvdrmengine/cdm/include/timer.h

@@ -9,6 +9,8 @@
 
 #include <stdint.h>
 
+#include "utils/StrongPointer.h"
+
 #include "disallow_copy_and_assign.h"
 
 namespace wvcdm {
@@ -45,7 +47,7 @@ class Timer {
   bool IsRunning();
 
  private:
-  Impl *impl_;
+  android::sp<Impl> impl_;
 
   CORE_DISALLOW_COPY_AND_ASSIGN(Timer);
 };

libwvdrmengine/cdm/src/timer.cpp

@@ -81,9 +81,6 @@ Timer::Timer() : impl_(new Timer::Impl()) {
 Timer::~Timer() {
   if (IsRunning())
     Stop();
-
-  delete impl_;
-  impl_ = NULL;
 }
 
 bool Timer::Start(TimerHandler *handler, uint32_t time_in_secs) {