[DML] Enable GPU memory trace dumps.

Adds `webnn_enable_resource_dump = true` to create a trace dump. Then open the dump in chrome://tracing to analyze GPU memory usage.

Author: bbernhar

build_overrides/webnn_features.gni

@@ -40,4 +40,5 @@ declare_args() {
 
   webnn_enable_wire = false
   webnn_enable_gpu_buffer = false
+  webnn_enable_resource_dump = false
 }

src/webnn/native/BUILD.gn

@@ -247,6 +247,10 @@ source_set("sources") {
     if (build_with_chromium == false) {
       include_dirs += [ "${webnn_root}/third_party/DirectML/Libraries" ]
     }
+
+    if (webnn_enable_resource_dump) {
+      defines = [ "WEBNN_ENABLE_RESOURCE_DUMP" ]
+    }
   }
 
   if (webnn_enable_dml || webnn_enable_dmlx) {

src/webnn/native/dmlx/deps/src/device.cpp

@@ -112,6 +112,13 @@ HRESULT Device::Init()
     allocatorDesc.Device = m_d3d12Device;
     allocatorDesc.IsUMA = arch.UMA;
     allocatorDesc.ResourceHeapTier = options.ResourceHeapTier;
+
+#ifdef WEBNN_ENABLE_RESOURCE_DUMP
+    allocatorDesc.RecordOptions.Flags |= gpgmm::d3d12::ALLOCATOR_RECORD_FLAG_ALL_EVENTS;
+    allocatorDesc.RecordOptions.MinMessageLevel = D3D12_MESSAGE_SEVERITY_MESSAGE;
+    allocatorDesc.RecordOptions.UseDetailedTimingEvents = true;
+#endif
+
     ReturnIfFailed(gpgmm::d3d12::ResourceAllocator::CreateAllocator(allocatorDesc, &m_resourceAllocator, &m_residencyManager));
 
     D3D12_DESCRIPTOR_HEAP_DESC descriptorHeapDesc = {};