clean up more dead code

src/core/SkTaskGroup.cpp

Index: src/core/SkTaskGroup.cpp
diff --git a/src/core/SkTaskGroup.cpp b/src/core/SkTaskGroup.cpp
index 1799256d6fe869a6d1fa58987302ecac739afdae..b3c23b649beaece214b2531a13569dc790aefd46 100644
--- a/src/core/SkTaskGroup.cpp
+++ b/src/core/SkTaskGroup.cpp
@@ -6,7 +6,6 @@
  */
 
 #include "SkOnce.h"
-#include "SkRunnable.h"
 #include "SkSemaphore.h"
 #include "SkSpinlock.h"
 #include "SkTArray.h"
@@ -40,13 +39,6 @@ namespace {
 
 class ThreadPool : SkNoncopyable {
 public:
-    static void Add(SkRunnable* task, SkAtomic<int32_t>* pending) {
-        if (!gGlobal) {  // If we have no threads, run synchronously.
-            return task->run();
-        }
-        gGlobal->add([task]() { task->run(); }, pending);
-    }
-
     static void Add(std::function<void(void)> fn, SkAtomic<int32_t>* pending) {
         if (!gGlobal) {
             return fn();
@@ -99,8 +91,6 @@ private:
         SkSpinlock* fLock;
     };
 
-    static void CallRunnable(void* arg) { static_cast<SkRunnable*>(arg)->run(); }
-
     struct Work {
         std::function<void(void)> fn; // A function to call
         SkAtomic<int32_t>* pending;   // then decrement pending afterwards.
@@ -213,7 +203,6 @@ SkTaskGroup::Enabler::~Enabler() { delete ThreadPool::gGlobal; }
 SkTaskGroup::SkTaskGroup() : fPending(0) {}
 
 void SkTaskGroup::wait()                            { ThreadPool::Wait(&fPending); }
-void SkTaskGroup::add(SkRunnable* task)             { ThreadPool::Add(task, &fPending); }
 void SkTaskGroup::add(std::function<void(void)> fn) { ThreadPool::Add(fn, &fPending); }
 void SkTaskGroup::batch(int N, std::function<void(int)> fn) {
     ThreadPool::Batch(N, fn, &fPending);