Enable extension support and debug layer.

src/gpu/vk/GrVkExtensions.h

Index: src/gpu/vk/GrVkExtensions.h
diff --git a/src/gpu/vk/GrVkExtensions.h b/src/gpu/vk/GrVkExtensions.h
new file mode 100644
index 0000000000000000000000000000000000000000..d1d57e424a8e3db07e6fa277798e72ab09cee7ab
--- /dev/null
+++ b/src/gpu/vk/GrVkExtensions.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrVkExtensions_DEFINED
+#define GrVkExtensions_DEFINED
+
+#include "../../private/SkTArray.h"
+#include "SkString.h"
+#include "vulkan/vulkan.h"
+
+/**
+ * This helper queries the current Vulkan context for its extensions and layers, remembers them, 
+ * and can be queried. It supports queries for both instance and device extensions and layers.
+ */
+class SK_API GrVkExtensions {
+public:
+    GrVkExtensions() : fInitialized(false)
+                     , fInstanceExtensionStrings(new SkTArray<SkString>)
+                     , fDeviceExtensionStrings(new SkTArray<SkString>)
+                     , fInstanceLayerStrings(new SkTArray<SkString>)
+                     , fDeviceLayerStrings(new SkTArray<SkString>) {}
+
+    GrVkExtensions(const GrVkExtensions&);
+
+    GrVkExtensions& operator=(const GrVkExtensions&);
+
+    void swap(GrVkExtensions* that) {
+        fInstanceExtensionStrings.swap(that->fInstanceExtensionStrings);
+        fDeviceExtensionStrings.swap(that->fDeviceExtensionStrings);
+        fInstanceLayerStrings.swap(that->fInstanceLayerStrings);
+        fDeviceLayerStrings.swap(that->fDeviceLayerStrings);
+
+        SkTSwap(fInitialized, that->fInitialized);
+    }
+
+    /**
+     * We sometimes need to use this class without having yet created a GrVkInterface. 
+     */
+    bool init(uint32_t specVersion,
+              PFN_vkEnumerateInstanceExtensionProperties enumerateInstanceExtensionProperties,
+              PFN_vkEnumerateDeviceExtensionProperties enumerateDeviceExtensionProperties,
+              PFN_vkEnumerateInstanceLayerProperties enumerateInstanceLayerProperties,
+              PFN_vkEnumerateDeviceLayerProperties enumerateDeviceLayerProperties);
+
+    bool isInitialized() const { return fInitialized; }
+
+    /**
+     * Queries whether an extension or layer is present. Will fail if init() has not been called.
+     */
+    bool hasInstanceExtension(const char[]) const;
+    bool hasDeviceExtension(const char[]) const;
+    bool hasInstanceLayer(const char[]) const;
+    bool hasDeviceLayer(const char[]) const;
+
+    /**
+     * Removes an extension or layer if present. Returns true if it was present before the call.
+     */
+    bool removeInstanceExtension(const char[]);
+    bool removeDeviceExtension(const char[]);
+    bool removeInstanceLayer(const char[]);
+    bool removeDeviceLayer(const char[]);
+
+    /**
+     * Adds an extension or layer to list
+     */
+    void addInstanceExtension(const char[]);
+    void addDeviceExtension(const char[]);
+    void addInstanceLayer(const char[]);
+    void addDeviceLayer(const char[]);
+
+    void reset() {
+        fInstanceExtensionStrings->reset();
+        fDeviceExtensionStrings->reset();
+        fInstanceLayerStrings->reset();
+        fDeviceLayerStrings->reset();
+    }
+
+    void print(const char* sep = "\n") const;
+
+private:
+    bool                                fInitialized;
+    SkAutoTDelete<SkTArray<SkString> >  fInstanceExtensionStrings;
+    SkAutoTDelete<SkTArray<SkString> >  fDeviceExtensionStrings;
+    SkAutoTDelete<SkTArray<SkString> >  fInstanceLayerStrings;
+    SkAutoTDelete<SkTArray<SkString> >  fDeviceLayerStrings;
+};
+
+#endif