Add a Toggle that can be disallowed for timestamp tick->ns conversion.

Bug: dawn:686
Change-Id: If017922ece2d98e95dedc922994807b85ca07397
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/41940
Reviewed-by: Stephen White <senorblanco@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>

src/dawn_native/CommandEncoder.cpp

@@ -850,7 +850,8 @@ namespace dawn_native {
             cmd->destinationOffset = destinationOffset;
 
             // Encode internal compute pipeline for timestamp query
-            if (querySet->GetQueryType() == wgpu::QueryType::Timestamp) {
+            if (querySet->GetQueryType() == wgpu::QueryType::Timestamp &&
+                GetDevice()->IsToggleEnabled(Toggle::ConvertTimestampsToNanoseconds)) {
                 EncodeTimestampsToNanosecondsConversion(this, querySet, queryCount, destination,
                                                         destinationOffset);
             }

src/dawn_native/Device.cpp

@@ -1191,6 +1191,7 @@ namespace dawn_native {
     void DeviceBase::SetDefaultToggles() {
         SetToggle(Toggle::LazyClearResourceOnFirstUse, true);
         SetToggle(Toggle::DisallowUnsafeAPIs, true);
+        SetToggle(Toggle::ConvertTimestampsToNanoseconds, true);
     }
 
     void DeviceBase::ApplyToggleOverrides(const DeviceDescriptor* deviceDescriptor) {

src/dawn_native/Toggles.cpp

@@ -167,6 +167,12 @@ namespace dawn_native {
              {"flush_before_client_wait_sync",
               "Call glFlush before glClientWaitSync to work around bugs in the latter",
               "https://crbug.com/dawn/633"}},
+            {Toggle::ConvertTimestampsToNanoseconds,
+             {"convert_timestamps_to_nanoseconds",
+              "If needed, use a compute shader to transform timestamp queries from ticks to "
+              "nanoseconds. This is temporarily needed to avoid requiring Tint to use timestamp "
+              "queries",
+              "https://crbug.com/dawn/686"}}
             // Dummy comment to separate the }} so it is clearer what to copy-paste to add a toggle.
         }};
 

src/dawn_native/Toggles.h

@@ -50,6 +50,7 @@ namespace dawn_native {
         DisallowUnsafeAPIs,
         UseTintGenerator,
         FlushBeforeClientWaitSync,
+        ConvertTimestampsToNanoseconds,
 
         EnumCount,
         InvalidEnum = EnumCount,