Move mirror::ArtMethod to native

Optimizing + quick tests are passing, devices boot.

TODO: Test and fix bugs in mips64.

Saves 16 bytes per most ArtMethod, 7.5MB reduction in system PSS.
Some of the savings are from removal of virtual methods and direct
methods object arrays.

Bug: 19264997
Change-Id: I622469a0cfa0e7082a2119f3d6a9491eb61e3f3d
diff --git a/compiler/compiler.h b/compiler/compiler.h
index 94b0fe3..e5d1aff 100644
--- a/compiler/compiler.h
+++ b/compiler/compiler.h
@@ -22,16 +22,13 @@
 
 namespace art {
 
+class ArtMethod;
 class Backend;
 struct CompilationUnit;
 class CompilerDriver;
 class CompiledMethod;
 class OatWriter;
 
-namespace mirror {
-  class ArtMethod;
-}
-
 class Compiler {
  public:
   enum Kind {
@@ -60,7 +57,7 @@
                                      uint32_t method_idx,
                                      const DexFile& dex_file) const = 0;
 
-  virtual uintptr_t GetEntryPointOf(mirror::ArtMethod* method) const
+  virtual uintptr_t GetEntryPointOf(ArtMethod* method) const
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
 
   uint64_t GetMaximumCompilationTimeBeforeWarning() const {