Break apart header files.

Create libart-gtest for common runtime and compiler gtest routines.
Rename CompilerCallbacksImpl that is quick compiler specific.
Rename trace clock source constants to not use the overloaded profiler term.

Change-Id: I4aac4bdc7e7850c68335f81e59a390133b54e933
diff --git a/runtime/gc/collector/mark_compact.h b/runtime/gc/collector/mark_compact.h
index 25cfe0f..bb85fa0 100644
--- a/runtime/gc/collector/mark_compact.h
+++ b/runtime/gc/collector/mark_compact.h
@@ -49,6 +49,7 @@
 }  // namespace accounting
 
 namespace space {
+  class BumpPointerSpace;
   class ContinuousMemMapAllocSpace;
   class ContinuousSpace;
 }  // namespace space