includes: move Label out of assembler.h.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index a4d97ec3e66480d29442b0958f0d10e32905c223..670251cdcee2e847108986c537da442f497187e6 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -235,17 +235,6 @@ unsigned CpuFeatures::icache_line_size_ = 0;
 unsigned CpuFeatures::dcache_line_size_ = 0;
 
 // -----------------------------------------------------------------------------
-// Implementation of Label
-
-int Label::pos() const {
-  if (pos_ < 0) return -pos_ - 1;
-  if (pos_ > 0) return  pos_ - 1;
-  UNREACHABLE();
-  return 0;
-}
-
-
-// -----------------------------------------------------------------------------
 // Implementation of RelocInfoWriter and RelocIterator
 //
 // Relocation information is written backwards in memory, from high addresses