Bug 1749183 - Fix RenderThread::HandleDeviceReset() for simulate device reset r=gfx-reviewers,aosmond

Current RenderThread::HandleDeviceReset() does nothing for simulate device reset.

Differential Revision: https://phabricator.services.mozilla.com/D135590

gfx/webrender_bindings/RenderThread.cpp

@@ -867,7 +867,22 @@ static DeviceResetReason GLenumToResetReason(GLenum aReason) {
 void RenderThread::HandleDeviceReset(const char* aWhere, GLenum aReason) {
   MOZ_ASSERT(IsInRenderThread());
 
+  // This happens only on simulate device reset.
   if (aReason == LOCAL_GL_NO_ERROR) {
+    MOZ_ASSERT(XRE_IsGPUProcess());
+
+    if (!mHandlingDeviceReset) {
+      mHandlingDeviceReset = true;
+
+      MutexAutoLock lock(mRenderTextureMapLock);
+      mRenderTexturesDeferred.clear();
+      for (const auto& entry : mRenderTextures) {
+        entry.second->ClearCachedResources();
+      }
+      // Simulate DeviceReset does not need to notify the device reset to
+      // GPUProcessManager. It is already done by
+      // GPUProcessManager::SimulateDeviceReset().
+    }
     return;
   }