Reduce namespace pollution.

This leaves us with just the mspace stuff and three libdex functions to clean
up. We deliberately expose the JII API, and I don't think there's anything we
can really do about the art_..._from_code stuff (and at least that starts with
"art_").

Change-Id: I77e58e8330cd2afeb496642302dfe3311e68091a
diff --git a/src/compiler/Compiler.h b/src/compiler/Compiler.h
index 224ea6e..ac5e0c9 100644
--- a/src/compiler/Compiler.h
+++ b/src/compiler/Compiler.h
@@ -19,6 +19,8 @@
 
 #include "dex_file.h"
 
+namespace art {
+
 #define COMPILER_TRACED(X)
 #define COMPILER_TRACEE(X)
 
@@ -103,8 +105,8 @@
 bool oatStartup(void);
 void oatShutdown(void);
 CompiledMethod* oatCompileMethod(const Compiler& compiler, bool is_direct,
-                                 uint32_t method_idx, const art::ClassLoader* class_loader,
-                                 const art::DexFile& dex_file, OatInstructionSetType);
+                                 uint32_t method_idx, const ClassLoader* class_loader,
+                                 const DexFile& dex_file, OatInstructionSetType);
 void oatDumpStats(void);
 void oatScanAllClassPointers(void (*callback)(void* ptr));
 void oatInitializeSSAConversion(struct CompilationUnit* cUnit);
@@ -135,4 +137,6 @@
 void oatDumpCFG(struct CompilationUnit* cUnit, const char* dirPrefix);
 void oatProcessSwitchTables(CompilationUnit* cUnit);
 
+}  // namespace art
+
 #endif // ART_SRC_COMPILER_COMPILER_H_