Bug 1806096 - Added check for front TextureClient lost by PersistentBufferProviderShared::SetKnowsCompositor() r=gfx-reviewers,lsalzman

Device reset could cause front TextureClient lost in PersistentBufferProviderShared::SetKnowsCompositor(). In this case, ShareableCanvasRenderer::UpdateCompositableClient() does not have TextureClient for compositor.

Differential Revision: https://phabricator.services.mozilla.com/D176748

gfx/layers/PersistentBufferProvider.cpp

@@ -228,8 +228,9 @@ PersistentBufferProviderShared::~PersistentBufferProviderShared() {
 }
 
 bool PersistentBufferProviderShared::SetKnowsCompositor(
-    KnowsCompositor* aKnowsCompositor) {
+    KnowsCompositor* aKnowsCompositor, bool& aOutLostFrontTexture) {
   MOZ_ASSERT(aKnowsCompositor);
+  MOZ_ASSERT(!aOutLostFrontTexture);
   if (!aKnowsCompositor) {
     return false;
   }
@@ -257,7 +258,9 @@ bool PersistentBufferProviderShared::SetKnowsCompositor(
     // Get rid of everything else
     Destroy();
 
-    if (prevTexture && prevTexture->IsValid()) {
+    if (prevTexture && !prevTexture->IsValid()) {
+      aOutLostFrontTexture = true;
+    } else if (prevTexture && prevTexture->IsValid()) {
       RefPtr<TextureClient> newTexture =
           CreateTexture(aKnowsCompositor, mFormat, mSize, mWillReadFrequently);
 

gfx/layers/PersistentBufferProvider.h

@@ -81,7 +81,8 @@ class PersistentBufferProvider : public RefCounted<PersistentBufferProvider>,
 
   virtual void OnShutdown() {}
 
-  virtual bool SetKnowsCompositor(KnowsCompositor* aKnowsCompositor) {
+  virtual bool SetKnowsCompositor(KnowsCompositor* aKnowsCompositor,
+                                  bool& aOutLostFrontTexture) {
     return true;
   }
 
@@ -207,7 +208,8 @@ class PersistentBufferProviderShared : public PersistentBufferProvider,
 
   void OnShutdown() override { Destroy(); }
 
-  bool SetKnowsCompositor(KnowsCompositor* aKnowsCompositor) override;
+  bool SetKnowsCompositor(KnowsCompositor* aKnowsCompositor,
+                          bool& aOutLostFrontTexture) override;
 
   void ClearCachedResources() override;
 

gfx/layers/ShareableCanvasRenderer.cpp

@@ -120,15 +120,19 @@ void ShareableCanvasRenderer::UpdateCompositableClient() {
   // -
 
   const auto fnGetExistingTc =
-      [&](const Maybe<SurfaceDescriptor>& aDesc) -> RefPtr<TextureClient> {
+      [&](const Maybe<SurfaceDescriptor>& aDesc,
+          bool& aOutLostFrontTexture) -> RefPtr<TextureClient> {
     if (aDesc) {
       return GetFrontBufferFromDesc(*aDesc, flags);
     }
     if (provider) {
-      if (!provider->SetKnowsCompositor(forwarder)) {
+      if (!provider->SetKnowsCompositor(forwarder, aOutLostFrontTexture)) {
         gfxCriticalNote << "BufferProvider::SetForwarder failed";
         return nullptr;
       }
+      if (aOutLostFrontTexture) {
+        return nullptr;
+      }
 
       return provider->GetTextureClient();
     }
@@ -196,7 +200,12 @@ void ShareableCanvasRenderer::UpdateCompositableClient() {
     EnsurePipeline();
 
     // Let's see if we can get a no-copy TextureClient from the canvas.
-    auto tc = fnGetExistingTc(desc);
+    bool lostFrontTexture = false;
+    auto tc = fnGetExistingTc(desc, lostFrontTexture);
+    if (lostFrontTexture) {
+      // Device reset could cause this.
+      return;
+    }
     if (!tc) {
       // Otherwise, snapshot the surface and copy into a TexClient.
       tc = fnMakeTcFromSnapshot();