Let DM run unit tests.

dm/DMTaskRunner.cpp

 #include "DMTaskRunner.h"
 #include "DMTask.h"
 
 namespace DM {
 
-TaskRunner::TaskRunner(int cputhreads, int gpuThreads)
+
+TaskRunner::TaskRunner(int cputhreads)
     : fMain(cputhreads)
-    , fGpu(gpuThreads)
-    {}
+    , fGpu(1) {
+    // Enqueue a task on the GPU thread to create a GrContextFactory.
+    struct Create : public SkRunnable {
+        Create(GrContextFactory** ptr) : fPtr(ptr) {}
+        void run() SK_OVERRIDE {
+            *fPtr = SkNEW(GrContextFactory);
+            delete this;
+        }
+        GrContextFactory** fPtr;
+    };
+    fGpu.add(SkNEW_ARGS(Create, (&fGrContextFactory)));
+}
 
 void TaskRunner::add(Task* task) {
     if (task->usesGpu()) {
         fGpu.add(task);
     } else {
         fMain.add(task);
     }
 }
 
 void TaskRunner::wait() {
+    // Enqueue a task on the GPU thread to destroy the GrContextFactory.
+    struct Delete : public SkRunnable {
+        Delete(GrContextFactory* ptr) : fPtr(ptr) {}
+        void run() SK_OVERRIDE {
+            delete fPtr;
+            delete this;
+        }
+        GrContextFactory* fPtr;
+    };
+    fGpu.add(SkNEW_ARGS(Delete, (fGrContextFactory)));
+
     // These wait calls block until the threadpool is done.  We don't allow
     // children to spawn new GPU tasks so we can wait for that first knowing
     // we'll never try to add to it later.  Same can't be said of fMain: fGpu
     // and fMain can both add tasks to fMain, so we have to wait for that last.
     fGpu.wait();
     fMain.wait();
 }
 
 }  // namespace DM