Clean up EGL thread state at thread exit in nanobench and DM

src/core/SkTaskGroup.cpp

Index: src/core/SkTaskGroup.cpp
diff --git a/src/core/SkTaskGroup.cpp b/src/core/SkTaskGroup.cpp
index b3c23b649beaece214b2531a13569dc790aefd46..1b542a63f51aed4e5548d335ae4d34ca614642e1 100644
--- a/src/core/SkTaskGroup.cpp
+++ b/src/core/SkTaskGroup.cpp
@@ -96,7 +96,8 @@ private:
         SkAtomic<int32_t>* pending;   // then decrement pending afterwards.
     };
 
-    explicit ThreadPool(int threads) {
+    explicit ThreadPool(int threads, std::function<void(void)> cleanupFn)
+        : fCleanupFn(cleanupFn) {
         if (threads == -1) {
             threads = sk_num_cores();
         }
@@ -161,6 +162,9 @@ private:
                 pool->fWork.pop_back();
             }
             if (!work.fn) {
+                if (pool->fCleanupFn) {
+                    pool->fCleanupFn();
+                }
                 return;  // Poison pill.  Time... to die.
             }
             work.fn();
@@ -183,6 +187,8 @@ private:
 
     // These are only changed in a single-threaded context.
     SkTDArray<SkThread*> fThreads;
+
+    std::function<void(void)> fCleanupFn;
     static ThreadPool* gGlobal;
 
     friend struct SkTaskGroup::Enabler;
@@ -191,14 +197,20 @@ ThreadPool* ThreadPool::gGlobal = nullptr;
 
 }  // namespace
 
-SkTaskGroup::Enabler::Enabler(int threads) {
+SkTaskGroup::Enabler::Enabler(int threads, std::function<void(void)> cleanupFn)
+    : fCleanupFn(cleanupFn) {
     SkASSERT(ThreadPool::gGlobal == nullptr);
     if (threads != 0) {
-        ThreadPool::gGlobal = new ThreadPool(threads);
+        ThreadPool::gGlobal = new ThreadPool(threads, cleanupFn);
     }
 }
 
-SkTaskGroup::Enabler::~Enabler() { delete ThreadPool::gGlobal; }
+SkTaskGroup::Enabler::~Enabler() {
+    if (!ThreadPool::gGlobal && fCleanupFn) {
+        fCleanupFn();
+    }
+    delete ThreadPool::gGlobal;
+}
 
 SkTaskGroup::SkTaskGroup() : fPending(0) {}