Fix compilation on ARM when adding Math.pow optimization in 5949.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
===================================================================
--- src/arm/lithium-arm.cc	(revision 5949)
+++ src/arm/lithium-arm.cc	(working copy)
@@ -1351,6 +1351,9 @@
       return AssignEnvironment(DefineAsRegister(result));
     case kMathSqrt:
       return DefineSameAsFirst(result);
+    case kMathPowHalf:
+      Abort("MathPowHalf LUnaryMathOperation not implemented");
+      return NULL;
     default:
       UNREACHABLE();
       return NULL;
@@ -1548,6 +1551,12 @@
 }
 
 
+LInstruction* LChunkBuilder::DoPower(HPower* instr) {
+  Abort("LPower instruction not implemented on ARM");
+  return NULL;
+}
+
+
 LInstruction* LChunkBuilder::DoCompare(HCompare* instr) {
   Token::Value op = instr->token();
   if (instr->left()->representation().IsInteger32()) {