Just makes sense cleanup

Test: gTest liblog-unit-tests
Bug: 33535908
Change-Id: I85de049f3cd73a473d56db5970d42eee5f9f70a8

Test: compile
Bug: 31992412
Change-Id: Idd52072d0f8c657ac53dc3e6b505a66c47a94357

Add private function __android_logger_get_buffer_size() to read
properties and compose the default buffer size.  This interface
complements the existing android_looger_get_size() which returns
the logd setting which can differ at runtime.  For use in logd
and dumpstate.  Side effect is we also add the private functions
__android_logger_property_get_bool() and
__android_logger_valid_buffer_size() for reuse in logd.

Test: gTest liblog-unit-test, logd-unit-tests and logcat-unit-tests in
      combination with commit 'logd: Use private interfaces for
      buffer size properties'
Bug: 31750617
Change-Id: Id95cb68f775ef6b427c122e10f6f8291d336d184

Allow our own libraries to use this privately instead of
running the less efficient get_properties and doing the math.

Test: compile and boot smoke test
Bug: 27566046
Bug: 31456426
Change-Id: I2f677276d27fbcb6af01b600ac1d9891c8938d43

Allows us to mitigate the impact of MAP_PRIVATE and copy on write by
calling android_lookupEventTag_len instead of android_lookupEventTag,
and delaying the copy on write impact to the later.  We return a
string length in a supplied location along with the string pointer
with android_lookupEventTag_len(const EventTagMap* map, size_t* len,
int tag).  The string is not guaranteed to be nul terminated.  Since
android_lookupEventTag() called even once can cause the memory
impact, we will mark it as deprecated, but we currently have no
timeframe for removal since this is a very old interface.

Add an API for __android_log_is_loggable_len() that accepts the non
null terminated content and fixup callers that would gain because the
length is known prior to the call either in the compiler or at
runtime.  Tackle transition to android_lookupEventTag_len() and
fixup callers.

On any application that performs logging (eg: com.android.phone)

/proc/<pid>/smaps before:

xxxxxxxxxx-xxxxxxxxxx rw-p 00000000 fd:00 463 /system/etc/event-log-tags
Size:                 20 kB
Rss:                  20 kB
Pss:                   1 kB
Shared_Clean:          0 kB
Shared_Dirty:         20 kB
Private_Clean:         0 kB
Private_Dirty:         0 kB
Referenced:            0 kB
Anonymous:            20 kB
AnonHugePages:         0 kB
Swap:                  0 kB
SwapPss:               0 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB
Locked:                0 kB
VmFlags: rd wr mr mw me ac

/proc/<pid>/smaps after:

xxxxxxxxxx-xxxxxxxxxx rw-p 00000000 fd:00 1773 /system/etc/event-log-tags
Size:                 20 kB
Rss:                  20 kB
Pss:                   1 kB
Shared_Clean:         20 kB  (was 0kB)
Shared_Dirty:          0 kB  (was 20kB)
Private_Clean:         0 kB
Private_Dirty:         0 kB
Referenced:           20 kB  (was 0kB)
Anonymous:             0 kB  (was 20kB)
AnonHugePages:         0 kB
Swap:                  0 kB
SwapPss:               0 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB
Locked:                0 kB
VmFlags: rd wr mr mw me ac

Added liblog-unit-tests --gtest_filter=liblog.event_log_tags to
check for Shared_Clean: to not be 0 and Anonymous: to be 0 for
all processes referencing event-log-tags.  Which can include multiple
references to /system/etc/event-log-tags and future possible refs to
/data/misc/logd/event-log-tags and /dev/event-log-tags.  We want
failure messages to help point to errant code using the deprecated
interface.

This change saves 1/4MB of memory or more on a typical system.

Test: gTest liblog-unit-tests
Bug: 31456426
Change-Id: I9e08e44d9092bd96fe704b5709242e7195281d33

- periodic failures in apct, dropped second serial test
  in refresh_cache, trusting check_cache or global.
- The retry loop to see if is_loggable recovers of 1000
  was hiding subsequent tests, drop to 10 retries.
- On the whole, the average performance remains the same.

Bug: 25792367
Change-Id: I4110440ef46671d7a1c128689bde623808bed04f

- add optimized & cached LIBLOG_HIDDEN __android_log_is_debuggable()
- check when writing, either LOG_ID_SECURITY, SafetyNet or
  debuggable when pushing content to the pmsg buffer.

Bug: 27566046
Change-Id: I85f1b55ec329b38e00f4183836b6ed53046c323d

Create config_logger, logger and logger_read to house the log
interfaces. Add fake_logger, logd_logger and pmsg_logger to
house the write and read transports. Allows for an easier and
direct path to add new transports to the library.

SideEffects: None, logger benchmark performance unaffected

Bug: 27176738
Bug: 27405083
Change-Id: I01b38637334a5242905c8c89f6ab0a92e2540008

- replace <sys/cdefs.h> with local "log_cdefs.h" which
  fortifies and expands definitions, adding LIBLOG_ABI_PUBLIC,
  LIBLOG_HIDDEN, LIBLOG_ABI_PRIVATE and LIBLOG_WEAK.
- clearly tag each interface as LIBLOG_ABI_PUBLIC, LIBLOG_HIDDEN,
  LIBLOG_ABI_PRIVATE, LIBLOG_WEAK or static depending on scope
- Add -fvisibility=hidden to ensure nothing else leaks
- some code standard adjustments

Bug: 27566046
Change-Id: Ic14033c4e6d833d973beb035ddc1c6134fb35a3f

strdup to a static pointer is unnecessary, strlcpy into a static buffer
instead.  Avoids allocations in the ALOG* path, allowing liblog to be
used by libmemleak.

Change-Id: Ie0986da27c1fc5eb8ce4ebb076b513be8e1ee676