Refactor programWalker.

- Pass variables computed in upper layers via args.
- declare variables prior to functions.
- Change some names for better verbosity.

Change-Id: I603b9ada1f62a08de5ac0fce177ccd840f2ce98c

runtime/command_queue/hardware_interface.h

@@ -88,12 +88,15 @@ class HardwareInterface {
         IndirectHeap &dsh,
         IndirectHeap &ioh,
         IndirectHeap &ssh,
+        size_t globalWorkSizes[3],
         size_t localWorkSizes[3],
         PreemptionMode preemptionMode,
         size_t currentDispatchIndex,
         uint32_t &interfaceDescriptorIndex,
         const DispatchInfo &dispatchInfo,
-        size_t offsetInterfaceDescriptorTable);
+        size_t offsetInterfaceDescriptorTable,
+        Vec3<size_t> &numberOfWorkgroups,
+        Vec3<size_t> &startOfWorkgroups);
 
     static WALKER_TYPE<GfxFamily> *allocateWalkerSpace(LinearStream &commandStream,
                                                        const Kernel &kernel);