More advanced timing loggers.

The new timing loggers have lower overhead since they only push into
a vector. The new format has two types, a start timing and a stop
timing. You can thing of these as brackets associated with a
timestamp. It uses these to construct various statistics when needed,
such as: Total time, exclusive time, and nesting depth.

Changed PrettyDuration to have a default of 3 digits after the decimal
point.

Exaple of a GC dump with exclusive / total times and indenting:
I/art     (23546): GC iteration timing logger [Exclusive time] [Total time]
I/art     (23546):   0ms InitializePhase
I/art     (23546):   0.305ms/167.746ms MarkingPhase
I/art     (23546):     0ms BindBitmaps
I/art     (23546):     0ms FindDefaultSpaceBitmap
I/art     (23546):     0ms/1.709ms ProcessCards
I/art     (23546):       0.183ms ImageModUnionClearCards
I/art     (23546):       0.916ms ZygoteModUnionClearCards
I/art     (23546):       0.610ms AllocSpaceClearCards
I/art     (23546):       1.373ms AllocSpaceClearCards
I/art     (23546):     0.305ms/6.318ms MarkRoots
I/art     (23546):       2.106ms MarkRootsCheckpoint
I/art     (23546):       0.153ms MarkNonThreadRoots
I/art     (23546):       4.287ms MarkConcurrentRoots
I/art     (23546):     43.461ms UpdateAndMarkImageModUnionTable
I/art     (23546):     0ms/112.712ms RecursiveMark
I/art     (23546):       112.712ms ProcessMarkStack
I/art     (23546):     0.610ms/2.777ms PreCleanCards
I/art     (23546):       0.305ms/0.855ms ProcessCards
I/art     (23546):         0.153ms ImageModUnionClearCards
I/art     (23546):         0.610ms ZygoteModUnionClearCards
I/art     (23546):         0.610ms AllocSpaceClearCards
I/art     (23546):         0.549ms AllocSpaceClearCards
I/art     (23546):       0.549ms MarkRootsCheckpoint
I/art     (23546):       0.610ms MarkNonThreadRoots
I/art     (23546):       0ms MarkConcurrentRoots
I/art     (23546):       0.610ms ScanGrayImageSpaceObjects
I/art     (23546):       0.305ms ScanGrayZygoteSpaceObjects
I/art     (23546):       0.305ms ScanGrayAllocSpaceObjects
I/art     (23546):       1.129ms ScanGrayAllocSpaceObjects
I/art     (23546):       0ms ProcessMarkStack
I/art     (23546):   0ms/0.977ms (Paused)PausePhase
I/art     (23546):     0.244ms ReMarkRoots
I/art     (23546):     0.672ms (Paused)ScanGrayObjects
I/art     (23546):     0ms (Paused)ProcessMarkStack
I/art     (23546):     0ms/0.610ms SwapStacks
I/art     (23546):       0.610ms RevokeAllThreadLocalAllocationStacks
I/art     (23546):     0ms PreSweepingGcVerification
I/art     (23546):   0ms/10.621ms ReclaimPhase
I/art     (23546):     0.610ms/0.702ms ProcessReferences
I/art     (23546):       0.214ms/0.641ms EnqueueFinalizerReferences
I/art     (23546):         0.427ms ProcessMarkStack
I/art     (23546):     0.488ms SweepSystemWeaks
I/art     (23546):     0.824ms/9.400ms Sweep
I/art     (23546):       0ms SweepMallocSpace
I/art     (23546):       0.214ms SweepZygoteSpace
I/art     (23546):       0.122ms SweepMallocSpace
I/art     (23546):       6.226ms SweepMallocSpace
I/art     (23546):       0ms SweepMallocSpace
I/art     (23546):       2.144ms SweepLargeObjects
I/art     (23546):     0.305ms SwapBitmaps
I/art     (23546):     0ms UnBindBitmaps
I/art     (23546):   0.275ms FinishPhase
I/art     (23546): GC iteration timing logger: end, 178.971ms

Change-Id: Ia55b65609468f212b3cd65cda66b843da42be645
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 4590880..e1b6992 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -91,31 +91,31 @@
     size_oat_class_method_offsets_(0) {
   size_t offset;
   {
-    TimingLogger::ScopedSplit split("InitOatHeader", timings);
+    TimingLogger::ScopedTiming split("InitOatHeader", timings);
     offset = InitOatHeader();
   }
   {
-    TimingLogger::ScopedSplit split("InitOatDexFiles", timings);
+    TimingLogger::ScopedTiming split("InitOatDexFiles", timings);
     offset = InitOatDexFiles(offset);
   }
   {
-    TimingLogger::ScopedSplit split("InitDexFiles", timings);
+    TimingLogger::ScopedTiming split("InitDexFiles", timings);
     offset = InitDexFiles(offset);
   }
   {
-    TimingLogger::ScopedSplit split("InitOatClasses", timings);
+    TimingLogger::ScopedTiming split("InitOatClasses", timings);
     offset = InitOatClasses(offset);
   }
   {
-    TimingLogger::ScopedSplit split("InitOatMaps", timings);
+    TimingLogger::ScopedTiming split("InitOatMaps", timings);
     offset = InitOatMaps(offset);
   }
   {
-    TimingLogger::ScopedSplit split("InitOatCode", timings);
+    TimingLogger::ScopedTiming split("InitOatCode", timings);
     offset = InitOatCode(offset);
   }
   {
-    TimingLogger::ScopedSplit split("InitOatCodeDexFiles", timings);
+    TimingLogger::ScopedTiming split("InitOatCodeDexFiles", timings);
     offset = InitOatCodeDexFiles(offset);
   }
   size_ = offset;