Add --threads to tests binary, to run non-GPU tests on multiple cores.

tests/GrContextFactoryTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
 
 // This is a GPU-backend specific test
 #if SK_SUPPORT_GPU
 #include "GrContextFactory.h"
 
-static void test_context_factory(skiatest::Reporter* reporter) {
-    GrContextFactory contextFactory;
+static void test_context_factory(skiatest::Reporter* reporter,
+                                 GrContextFactory* contextFactory) {
+    // Reset in case some other test has been using it first.
+    contextFactory->destroyContexts();
 
     // Before we ask for a context, we expect the GL context to not be there.
     REPORTER_ASSERT(reporter,
-                    NULL == contextFactory.getGLContext(GrContextFactory::kNative_GLContextType));
+                    NULL == contextFactory->getGLContext(GrContextFactory::kNative_GLContextType));
 
     // After we ask for a context, we expect that the GL context to be there.
-    contextFactory.get(GrContextFactory::kNative_GLContextType);
+    contextFactory->get(GrContextFactory::kNative_GLContextType);
     REPORTER_ASSERT(reporter,
-                    contextFactory.getGLContext(GrContextFactory::kNative_GLContextType) != NULL);
+                    contextFactory->getGLContext(GrContextFactory::kNative_GLContextType) != NULL);
 
     // If we did not ask for a context with the particular GL context, we would
     // expect the particular GL context to not be there.
     REPORTER_ASSERT(reporter,
-                    NULL == contextFactory.getGLContext(GrContextFactory::kNull_GLContextType));
+                    NULL == contextFactory->getGLContext(GrContextFactory::kNull_GLContextType));
 }
 
 
 #include "TestClassDef.h"
-DEFINE_TESTCLASS("GrContextFactory", GrContextFactoryClass, test_context_factory);
+DEFINE_GPUTESTCLASS("GrContextFactory", GrContextFactoryClass, test_context_factory);
 
 #endif