Post-Quick cleanup: Remove CompilationUnit.

Change-Id: I309411b0fffaaed1e218e2c34394bdf6e2f75b48
diff --git a/compiler/compiler.h b/compiler/compiler.h
index 97c60de..487a27f 100644
--- a/compiler/compiler.h
+++ b/compiler/compiler.h
@@ -27,8 +27,6 @@
 }
 
 class ArtMethod;
-class Backend;
-struct CompilationUnit;
 class CompilerDriver;
 class CompiledMethod;
 class OatWriter;
@@ -46,8 +44,7 @@
 
   virtual void UnInit() const = 0;
 
-  virtual bool CanCompileMethod(uint32_t method_idx, const DexFile& dex_file, CompilationUnit* cu)
-      const = 0;
+  virtual bool CanCompileMethod(uint32_t method_idx, const DexFile& dex_file) const = 0;
 
   virtual CompiledMethod* Compile(const DexFile::CodeItem* code_item,
                                   uint32_t access_flags,
@@ -77,8 +74,6 @@
     return maximum_compilation_time_before_warning_;
   }
 
-  virtual void InitCompilationUnit(CompilationUnit& cu) const = 0;
-
   virtual ~Compiler() {}
 
   /*