Add the webgpu.h swapchain creation path

This commit changes wgpu::Device::CreateSwapChain to take an additional
wgpu::Surface argument. Passing nullptr is enough to stay on the
previous swapchain implementation, until the new one is ready.

In order to support both the "old" implementation-based swapchains and
the "new" surface-based swapchains. SwapChainBase is now split into
three abstract classes:

 - SwapChainBase that has a virtual method for each of the
wgpu::SwapChain methods.
 - OldSwapChainBase that corresponds to the implementation-based
swapchains.
 - NewSwapChainBase that will contain the surface-based swapchain
implementation and will eventually just be renamed to SwapChainBase.

The interaction of the surface-based swapchains with the Surface objects
aren't implemented yet, neither are the swapchain methods. Only creation
works.

Validation tests for surface-based swapchain creation are added in the
end2end test target because they need to create OS windows.

Bug: dawn:269

Change-Id: I7e07d6c666479867b9a16d7b1b8c181d5dbd69a0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/15281
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>

src/dawn_native/opengl/DeviceGL.cpp

@@ -96,6 +96,11 @@ namespace dawn_native { namespace opengl {
         const SwapChainDescriptor* descriptor) {
         return new SwapChain(this, descriptor);
     }
+    ResultOrError<SwapChainBase*> Device::CreateSwapChainImpl(
+        Surface* surface,
+        const SwapChainDescriptor* descriptor) {
+        return DAWN_VALIDATION_ERROR("New swapchains not implemented.");
+    }
     ResultOrError<TextureBase*> Device::CreateTextureImpl(const TextureDescriptor* descriptor) {
         return new Texture(this, descriptor);
     }

src/dawn_native/opengl/DeviceGL.h

@@ -80,6 +80,9 @@ namespace dawn_native { namespace opengl {
             const ShaderModuleDescriptor* descriptor) override;
         ResultOrError<SwapChainBase*> CreateSwapChainImpl(
             const SwapChainDescriptor* descriptor) override;
+        ResultOrError<SwapChainBase*> CreateSwapChainImpl(
+            Surface* surface,
+            const SwapChainDescriptor* descriptor) override;
         ResultOrError<TextureBase*> CreateTextureImpl(const TextureDescriptor* descriptor) override;
         ResultOrError<TextureViewBase*> CreateTextureViewImpl(
             TextureBase* texture,

src/dawn_native/opengl/SwapChainGL.cpp

@@ -23,7 +23,7 @@
 namespace dawn_native { namespace opengl {
 
     SwapChain::SwapChain(Device* device, const SwapChainDescriptor* descriptor)
-        : SwapChainBase(device, descriptor) {
+        : OldSwapChainBase(device, descriptor) {
         const auto& im = GetImplementation();
         im.Init(im.userData, nullptr);
     }

src/dawn_native/opengl/SwapChainGL.h

@@ -23,7 +23,7 @@ namespace dawn_native { namespace opengl {
 
     class Device;
 
-    class SwapChain : public SwapChainBase {
+    class SwapChain : public OldSwapChainBase {
       public:
         SwapChain(Device* device, const SwapChainDescriptor* descriptor);
         ~SwapChain();