wvcdm: filter logs by app uid

This commit is a combination of the following:
* http://go/wvgerrit/117003
* http://go/wvgerrit/118303

Bug: 162255728
Test: MediaDrmTest#testGetLogMessages
Change-Id: I5699b64d5c4bab463e5b587595fa7d324dc1d93f

libwvdrmengine/cdm/util/include/log.h

@@ -33,6 +33,7 @@ typedef enum {
 extern LogPriority g_cutoff;
 
 struct LogMessage {
+  uint32_t uid_;
   int64_t time_ms_;
   LogPriority priority_;
   std::string message_;
@@ -51,6 +52,26 @@ class LogBuffer {
 
 extern LogBuffer g_logbuf;
 
+static const uint32_t UNKNOWN_UID = ~0;
+
+#ifdef __ANDROID__
+void SetLoggingUid(const uint32_t);
+void ClearLoggingUid();
+uint32_t GetLoggingUid();
+uint32_t GetIpcCallingUid();
+#else
+static inline void SetLoggingUid(const uint32_t) {}
+static inline void ClearLoggingUid() {}
+static inline uint32_t GetLoggingUid() { return UNKNOWN_UID; }
+static inline uint32_t GetIpcCallingUid() { return UNKNOWN_UID; }
+#endif
+
+struct LoggingUidSetter {
+  LoggingUidSetter() {}
+  LoggingUidSetter(uint32_t uid) { SetLoggingUid(uid); }
+  virtual ~LoggingUidSetter() { ClearLoggingUid(); }
+};
+
 // Enable/disable verbose logging (LOGV).
 // This function is supplied for cases where the system layer does not
 // initialize logging.  This is also needed to initialize logging in