Add begin-capture-on-startup testing flag

In order to debug single frame applications such as unit tests with
with PIX, you need to call BeginCapture() at the start of your
application.

This change adds a begin-capture-on-startup flag to the Dawn test
environment. The flag, when set, will call BeginCapture() right after
the DXGI factory is created.

Bug: dawn:44
Change-Id: Ibb8f7b05707915510f9886524f0144c0576d2603
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/8200
Commit-Queue: Rafael Cintron <rafael.cintron@microsoft.com>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>

src/tests/DawnTest.cpp

@@ -109,13 +109,20 @@ DawnTestEnvironment::DawnTestEnvironment(int argc, char** argv) {
             continue;
         }
 
+        if (strcmp("-c", argv[i]) == 0 || strcmp("--begin-capture-on-startup", argv[i]) == 0) {
+            mBeginCaptureOnStartup = true;
+            continue;
+        }
+
         if (strcmp("-h", argv[i]) == 0 || strcmp("--help", argv[i]) == 0) {
             std::cout << "\n\nUsage: " << argv[0]
-                      << " [GTEST_FLAGS...] [-w] [--enable-validation-layers]\n";
-            std::cout << "  -w, --use-wire: Run the tests through the wire (defaults to no wire)\n";
-            std::cout << "  -d, --enable-backend-validation: Enable backend validation (defaults"
-                      << " to disabled)\n";
-            std::cout << std::endl;
+                      << " [GTEST_FLAGS...] [-w] [--enable-validation-layers]\n"
+                         "  -w, --use-wire: Run the tests through the wire (defaults to no wire)\n"
+                         "  -d, --enable-backend-validation: Enable backend validation (defaults"
+                         " to disabled)\n"
+                         "  -c, --begin-capture-on-startup: Begin debug capture on startup "
+                         "(defaults to no capture)"
+                      << std::endl;
             continue;
         }
     }
@@ -126,6 +133,7 @@ void DawnTestEnvironment::SetUp() {
 
     mInstance = std::make_unique<dawn_native::Instance>();
     mInstance->EnableBackendValidation(mEnableBackendValidation);
+    mInstance->EnableBeginCaptureOnStartup(mBeginCaptureOnStartup);
 
     static constexpr dawn_native::BackendType kAllBackends[] = {
         dawn_native::BackendType::D3D12,
@@ -142,12 +150,18 @@ void DawnTestEnvironment::SetUp() {
         }
     }
 
-    std::cout << "Testing configuration\n";
-    std::cout << "---------------------\n";
-    std::cout << "UseWire: " << (mUseWire ? "true" : "false") << "\n";
-    std::cout << "EnableBackendValidation: " << (mEnableBackendValidation ? "true" : "false")
-              << "\n";
-    std::cout << "\n";
+    std::cout << "Testing configuration\n"
+                 "---------------------\n"
+                 "UseWire: "
+              << (mUseWire ? "true" : "false")
+              << "\n"
+                 "EnableBackendValidation: "
+              << (mEnableBackendValidation ? "true" : "false")
+              << "\n"
+                 "BeginCaptureOnStartup: "
+              << (mBeginCaptureOnStartup ? "true" : "false")
+              << "\n"
+                 "\n";
 
     // Preparing for outputting hex numbers
     std::cout << std::showbase << std::hex << std::setfill('0') << std::setw(4);

src/tests/DawnTest.h

@@ -117,6 +117,7 @@ class DawnTestEnvironment : public testing::Environment {
 
     bool mUseWire = false;
     bool mEnableBackendValidation = false;
+    bool mBeginCaptureOnStartup = false;
     std::unique_ptr<dawn_native::Instance> mInstance;
 
     // Windows don't usually like to be bound to one API than the other, for example switching