Update samples to process events.

This CL updates the `dawn/sample` programs to call the
`dawn::native::InstanceProcessEvents` which allows things like shader
validation errors to be emitted.

Without this change the errors are never displayed.

Change-Id: I054bb4f7177c5d0c110e97409852143b2bef1e02
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/126760
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>

src/dawn/samples/Animometer.cpp

@@ -186,6 +186,7 @@ int main(int argc, const char* argv[]) {
     timer->Start();
     while (!ShouldQuit()) {
         utils::ScopedAutoreleasePool pool;
+        ProcessEvents();
         frameCount++;
         frame();
         if (frameCount % 60 == 0) {

src/dawn/samples/CHelloTriangle.cpp

@@ -143,6 +143,7 @@ int main(int argc, const char* argv[]) {
 
     while (!ShouldQuit()) {
         utils::ScopedAutoreleasePool pool;
+        ProcessEvents();
         frame();
         utils::USleep(16000);
     }

src/dawn/samples/ComputeBoids.cpp

@@ -323,6 +323,7 @@ int main(int argc, const char* argv[]) {
 
     while (!ShouldQuit()) {
         utils::ScopedAutoreleasePool pool;
+        ProcessEvents();
         frame();
         utils::USleep(16000);
     }

src/dawn/samples/CppHelloTriangle.cpp

@@ -176,6 +176,7 @@ int main(int argc, const char* argv[]) {
 
     while (!ShouldQuit()) {
         utils::ScopedAutoreleasePool pool;
+        ProcessEvents();
         frame();
         utils::USleep(16000);
     }

src/dawn/samples/ManualSwapChainTest.cpp

@@ -339,6 +339,7 @@ int main(int argc, const char* argv[]) {
     while (windows.size() != 0) {
         utils::ScopedAutoreleasePool pool;
         glfwPollEvents();
+        wgpuInstanceProcessEvents(instance->Get());
 
         for (auto it = windows.begin(); it != windows.end();) {
             GLFWwindow* window = it->first;

src/dawn/samples/SampleUtils.cpp

@@ -391,3 +391,7 @@ bool ShouldQuit() {
 GLFWwindow* GetGLFWWindow() {
     return window;
 }
+
+void ProcessEvents() {
+    dawn::native::InstanceProcessEvents(instance->Get());
+}

src/dawn/samples/SampleUtils.h

@@ -28,5 +28,6 @@ wgpu::Device CreateCppDawnDevice();
 wgpu::TextureFormat GetPreferredSwapChainTextureFormat();
 wgpu::SwapChain GetSwapChain();
 wgpu::TextureView CreateDefaultDepthStencilView(const wgpu::Device& device);
+void ProcessEvents();
 
 #endif  // SRC_DAWN_SAMPLES_SAMPLEUTILS_H_