dawn_native: Factor getting procs into a single function.

Now the backends only expose the creation of devices. Getting the procs
is moved to DawnNative that will over time more backend-agnostic APIs.

src/tests/DawnTest.cpp

@@ -17,6 +17,7 @@
 #include "common/Assert.h"
 #include "common/Constants.h"
 #include "common/Math.h"
+#include "dawn_native/DawnNative.h"
 #include "dawn_wire/Wire.h"
 #include "utils/BackendBinding.h"
 #include "utils/DawnHelpers.h"
@@ -136,9 +137,8 @@ void DawnTest::SetUp() {
 
     mBinding->SetWindow(testWindow);
 
-    dawnDevice backendDevice;
-    dawnProcTable backendProcs;
-    mBinding->GetProcAndDevice(&backendProcs, &backendDevice);
+    dawnDevice backendDevice = mBinding->CreateDevice();
+    dawnProcTable backendProcs = dawn_native::GetProcs();
 
     // Choose whether to use the backend procs and devices directly, or set up the wire.
     dawnDevice cDevice = nullptr;

src/tests/unittests/validation/ValidationTest.cpp

@@ -15,6 +15,8 @@
 #include "tests/unittests/validation/ValidationTest.h"
 
 #include "dawn/dawn.h"
+#include "dawn_native/DawnNative.h"
+#include "dawn_native/NullBackend.h"
 
 namespace dawn_native {
     namespace null {
@@ -23,9 +25,8 @@ namespace dawn_native {
 }
 
 ValidationTest::ValidationTest() {
-    dawnProcTable procs;
-    dawnDevice cDevice;
-    dawn_native::null::Init(&procs, &cDevice);
+    dawnProcTable procs = dawn_native::GetProcs();
+    dawnDevice cDevice = dawn_native::null::CreateDevice();
 
     dawnSetProcs(&procs);
     device = dawn::Device::Acquire(cDevice);