logd: replace internal CLOCK_MONOTONIC use with sequence numbers

- switch to simpler and faster internal sequence number, drops
  a syscall overhead on 32-bit platforms.
- add ability to break-out of flushTo loop with filter return -1
  allowing in reduction in reader overhead.

Change-Id: Ic5cb2b9afa4d9470153971fc9197b07279e2b79d
diff --git a/logd/LogTimes.h b/logd/LogTimes.h
index 81aedfb..ae2f92b 100644
--- a/logd/LogTimes.h
+++ b/logd/LogTimes.h
@@ -47,13 +47,12 @@
 public:
     LogTimeEntry(LogReader &reader, SocketClient *client, bool nonBlock,
                  unsigned long tail, unsigned int logMask, pid_t pid,
-                 log_time start);
+                 uint64_t start);
 
     SocketClient *mClient;
-    static const struct timespec EPOCH;
-    log_time mStart;
+    uint64_t mStart;
     const bool mNonBlock;
-    const log_time mEnd; // only relevant if mNonBlock
+    const uint64_t mEnd; // only relevant if mNonBlock
 
     // Protect List manipulations
     static void lock(void) { pthread_mutex_lock(&timesLock); }
@@ -103,8 +102,8 @@
     }
     bool isWatching(log_id_t id) { return (mLogMask & (1<<id)) != 0; }
     // flushTo filter callbacks
-    static bool FilterFirstPass(const LogBufferElement *element, void *me);
-    static bool FilterSecondPass(const LogBufferElement *element, void *me);
+    static int FilterFirstPass(const LogBufferElement *element, void *me);
+    static int FilterSecondPass(const LogBufferElement *element, void *me);
 };
 
 typedef android::List<LogTimeEntry *> LastLogTimes;