Create specialized code stubs for PixelArray loads.

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
diff --git a/src/ia32/macro-assembler-ia32.h b/src/ia32/macro-assembler-ia32.h
index 6f180c6c2bcd822e2b7751badc6ba5b646463598..12a8923113824a033f9eaabb1347224ee44e4a26 100644
--- a/src/ia32/macro-assembler-ia32.h
+++ b/src/ia32/macro-assembler-ia32.h
@@ -258,6 +258,17 @@ class MacroAssembler: public Assembler {
     j(not_carry, is_smi);
   }
 
+  // Jump the register contains a smi.
+  inline void JumpIfSmi(Register value, Label* smi_label) {
+    test(value, Immediate(kSmiTagMask));
+    j(zero, smi_label, not_taken);
+  }
+  // Jump if register contain a non-smi.
+  inline void JumpIfNotSmi(Register value, Label* not_smi_label) {
+    test(value, Immediate(kSmiTagMask));
+    j(not_zero, not_smi_label, not_taken);
+  }
+
   // Assumes input is a heap object.
   void JumpIfNotNumber(Register reg, TypeInfo info, Label* on_not_number);