Add base class for GLTestContext and add new subclass VkTestContext.

tools/gpu/TestContext.cpp

Index: tools/gpu/TestContext.cpp
diff --git a/tools/gpu/TestContext.cpp b/tools/gpu/TestContext.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..09174cd984896cc358dd2a304c99827d9b7bd86f
--- /dev/null
+++ b/tools/gpu/TestContext.cpp
@@ -0,0 +1,67 @@
+
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "TestContext.h"
+
+namespace sk_gpu_test {
+TestContext::TestContext() : fFenceSync(nullptr), fCurrentFenceIdx(0) {
+    memset(fFrameFences, 0, sizeof(fFrameFences));
+}
+
+TestContext::~TestContext() {
+    // Subclass should call teardown.
+#ifdef SK_DEBUG
+    for (size_t i = 0; i < SK_ARRAY_COUNT(fFrameFences); i++) {
+        SkASSERT(0 == fFrameFences[i]);
+    }
+#endif
+    SkASSERT(!fFenceSync);
+}
+
+void TestContext::makeCurrent() const { this->onPlatformMakeCurrent(); }
+
+void TestContext::swapBuffers() { this->onPlatformSwapBuffers(); }
+
+void TestContext::waitOnSyncOrSwap() {
+    if (!fFenceSync) {
+        // Fallback on the platform SwapBuffers method for synchronization. This may have no effect.
+        this->swapBuffers();
+        return;
+    }
+
+    if (fFrameFences[fCurrentFenceIdx]) {
+        if (!fFenceSync->waitFence(fFrameFences[fCurrentFenceIdx], true)) {
+            SkDebugf("WARNING: Wait failed for fence sync. Timings might not be accurate.\n");
+        }
+        fFenceSync->deleteFence(fFrameFences[fCurrentFenceIdx]);
+    }
+
+    fFrameFences[fCurrentFenceIdx] = fFenceSync->insertFence();
+    fCurrentFenceIdx = (fCurrentFenceIdx + 1) % SK_ARRAY_COUNT(fFrameFences);
+}
+
+void TestContext::testAbandon() {
+    if (fFenceSync) {
+        memset(fFrameFences, 0, sizeof(fFrameFences));
+    }
+}
+
+void TestContext::teardown() {
+    if (fFenceSync) {
+        for (size_t i = 0; i < SK_ARRAY_COUNT(fFrameFences); i++) {
+            if (fFrameFences[i]) {
+                fFenceSync->deleteFence(fFrameFences[i]);
+                fFrameFences[i] = 0;
+            }
+        }
+        delete fFenceSync;
+        fFenceSync = nullptr;
+    }
+}
+
+}