Cleanup Compositor creation code path

Override both ConfigureAPZCTreeManager and ConfigureAPZControllerThread
to simplify compositor creation. The nsBaseWidget::CreateCompositor
calls virtual ConfigureAPZCTreeManager that shall not do anything as
APZTreeManager is configured elsewhere.

embedding/embedlite/embedshared/EmbedLitePuppetWidget.cpp

@@ -796,81 +796,10 @@ void EmbedLitePuppetWidget::CreateCompositor()
   CreateCompositor(size.width, size.height);
 }
 
-static void
-CheckForBasicBackends(nsTArray<LayersBackend>& aHints)
-{
-  for (size_t i = 0; i < aHints.Length(); ++i) {
-    if (aHints[i] == LayersBackend::LAYERS_BASIC &&
-        !Preferences::GetBool("layers.offmainthreadcomposition.force-basic", false) &&
-        !Preferences::GetBool("browser.tabs.remote", false)) {
-      // basic compositor is not stable enough for regular use
-      aHints[i] = LayersBackend::LAYERS_NONE;
-    }
-  }
-}
-
 void EmbedLitePuppetWidget::CreateCompositor(int aWidth, int aHeight)
 {
   LOGT();
-
-  // This makes sure that gfxPlatforms gets initialized if it hasn't by now.
-  gfxPlatform::GetPlatform();
-
-  MOZ_ASSERT(gfxPlatform::UsesOffMainThreadCompositing(),
-             "This function assumes OMTC");
-
-  MOZ_ASSERT(!mCompositorParent,
-    "Should have properly cleaned up the previous CompositorParent beforehand");
-
-  CreateCompositorVsyncDispatcher();
-  mCompositorParent = NewCompositorParent(aWidth, aHeight);
-//  MessageChannel* parentChannel = mCompositorParent->GetIPCChannel();
-  RefPtr<ClientLayerManager> lm = new ClientLayerManager(this);
-//  MessageLoop* childMessageLoop = CompositorParent::CompositorLoop();
-  mCompositorChild = new CompositorChild(lm);
-//  mCompositorChild->Open(parentChannel, childMessageLoop, ipc::ChildSide);
-  mCompositorChild->OpenSameProcess(mCompositorParent);
-
-  // Make sure the parent knows it is same process.
-  mCompositorParent->SetOtherProcessId(base::GetCurrentProcId());
-
-  TextureFactoryIdentifier textureFactoryIdentifier;
-  PLayerTransactionChild* shadowManager = nullptr;
-
-  nsTArray<LayersBackend> backendHints;
-  gfxPlatform::GetPlatform()->GetCompositorBackends(ComputeShouldAccelerate(), backendHints);
-
-  CheckForBasicBackends(backendHints);
-
-  bool success = false;
-  if (!backendHints.IsEmpty()) {
-    shadowManager = mCompositorChild->SendPLayerTransactionConstructor(
-      backendHints, 0, &textureFactoryIdentifier, &success);
-  }
-
-  ShadowLayerForwarder* lf = lm->AsShadowForwarder();
-  if (!success || !lf) {
-    NS_WARNING("Failed to create an OMT compositor.");
-    DestroyCompositor();
-    mLayerManager = nullptr;
-    mCompositorChild = nullptr;
-    mCompositorParent = nullptr;
-    mCompositorVsyncDispatcher = nullptr;
-    return;
-  }
-
-  lf->SetShadowManager(shadowManager);
-  lf->IdentifyTextureHost(textureFactoryIdentifier);
-  ImageBridgeChild::IdentifyCompositorTextureHost(textureFactoryIdentifier);
-  WindowUsesOMTC();
-
-  mLayerManager = lm.forget();
-
-  if (mWindowType == eWindowType_toplevel) {
-    // Only track compositors for top-level windows, since other window types
-    // may use the basic compositor.
-    gfxPlatform::GetPlatform()->NotifyCompositorCreated(mLayerManager->GetCompositorBackendType());
-  }
+  nsBaseWidget::CreateCompositor(aWidth, aHeight);
 }
 
 void
@@ -1009,5 +938,21 @@ EmbedLitePuppetWidget::GetEmbedLiteChildView() const
   return nullptr;
 }
 
+void EmbedLitePuppetWidget::ConfigureAPZCTreeManager()
+{
+  LOGT("Do nothing - APZEventState configured in EmbedLiteViewBaseChild");
+}
+
+void EmbedLitePuppetWidget::ConfigureAPZControllerThread()
+{
+  LOGT("Do nothing - APZController thread configured in EmbedLiteViewBaseParent");
+}
+
+already_AddRefed<GeckoContentController>
+EmbedLitePuppetWidget::CreateRootContentController()
+{
+  return nullptr;
+}
+
 }  // namespace widget
 }  // namespace mozilla

embedding/embedlite/embedshared/EmbedLitePuppetWidget.h

@@ -211,6 +211,10 @@ class EmbedLitePuppetWidget : public nsBaseWidget
   virtual ~EmbedLitePuppetWidget() override;
   EmbedLiteViewChildIface* GetEmbedLiteChildView() const;
 
+  virtual void ConfigureAPZCTreeManager();
+  virtual void ConfigureAPZControllerThread();
+  virtual already_AddRefed<GeckoContentController> CreateRootContentController() override;
+
 private:
   EmbedLitePuppetWidget();
   typedef nsTArray<EmbedLitePuppetWidget*> ChildrenArray;