Systrace fixups and refactoring for TimingLogger

Fixed systrace bounds for timing logger in GC. Refactored CumulativeLogger a bit to
allow for multiple identical entries. Added ScopedSplit, now composes with explicit
start/end/new splits. Adds some unit tests.
Bug: 10036801

Change-Id: If0afb88b48ec3a1e19462ed354babb274a9517a7
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index ac3b821..498f7ef 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -25,6 +25,7 @@
 	runtime/barrier_test.cc \
 	runtime/base/histogram_test.cc \
 	runtime/base/mutex_test.cc \
+	runtime/base/timing_logger_test.cc \
 	runtime/base/unix_file/fd_file_test.cc \
 	runtime/base/unix_file/mapped_file_test.cc \
 	runtime/base/unix_file/null_file_test.cc \