SW backend for viewer on Windows
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2182273002

Review-Url: https://codereview.chromium.org/2182273002
diff --git a/tools/viewer/sk_app/VulkanWindowContext.h b/tools/viewer/sk_app/VulkanWindowContext.h
index d40adf6..1953d75 100644
--- a/tools/viewer/sk_app/VulkanWindowContext.h
+++ b/tools/viewer/sk_app/VulkanWindowContext.h
@@ -28,7 +28,7 @@
 
     bool isValid() override { return SkToBool(fBackendContext.get()); }
 
-    void resize(uint32_t w, uint32_t h) override {
+    void resize(int w, int h) override {
         this->createSwapchain(w, h, fDisplayParams);
     }
 
@@ -59,7 +59,7 @@
     };
 
     BackbufferInfo* getAvailableBackbuffer();
-    bool createSwapchain(uint32_t width, uint32_t height, const DisplayParams& params);
+    bool createSwapchain(int width, int height, const DisplayParams& params);
     void createBuffers(VkFormat format);
     void destroyBuffers();