ART: Some runtime cleanup

Use an enum for the compiler-callback mode.

Refactor and remove some unnecessary includes in runtime.h.

Change-Id: If2245fa470171311b8e05b677cf6bb28f209585a
diff --git a/compiler/jit/jit_compiler.cc b/compiler/jit/jit_compiler.cc
index d034736..df5d5cc 100644
--- a/compiler/jit/jit_compiler.cc
+++ b/compiler/jit/jit_compiler.cc
@@ -90,7 +90,7 @@
   method_inliner_map_.reset(new DexFileToMethodInlinerMap);
   callbacks_.reset(new QuickCompilerCallbacks(verification_results_.get(),
                                               method_inliner_map_.get(),
-                                              false));
+                                              CompilerCallbacks::CallbackMode::kCompileApp));
   compiler_driver_.reset(new CompilerDriver(
       compiler_options_.get(), verification_results_.get(), method_inliner_map_.get(),
       Compiler::kQuick, instruction_set, instruction_set_features_.get(), false,