Bug 1405481 - Push canvas updates to the compositor on empty transactions r=jrmuizel

gfx/layers/ipc/PWebRenderBridge.ipdl

@@ -59,6 +59,9 @@ parent:
                           WebRenderScrollData aScrollData,
                           OpUpdateResource[] aResourceUpdates, Shmem[] aSmallShmems, Shmem[] aLargeShmems,
                           IdNamespace aIdNamespace, TimeStamp txnStartTime, TimeStamp fwdTime);
+  async EmptyTransaction(FocusTarget focusTarget,
+                         WebRenderParentCommand[] commands, OpDestroy[] toDestroy, uint64_t fwdTransactionId, uint64_t transactionId,
+                         IdNamespace aIdNamespace, TimeStamp txnStartTime, TimeStamp fwdTime);
   async SetFocusTarget(FocusTarget focusTarget);
   async UpdateResources(OpUpdateResource[] aResourceUpdates, Shmem[] aSmallShmems, Shmem[] aLargeShmems);
   async ParentCommands(WebRenderParentCommand[] commands);

gfx/layers/wr/WebRenderBridgeChild.cpp

@@ -157,6 +157,28 @@ WebRenderBridgeChild::EndTransaction(const wr::LayoutSize& aContentSize,
   mIsInTransaction = false;
 }
 
+void
+WebRenderBridgeChild::EndEmptyTransaction(const FocusTarget& aFocusTarget,
+                                          uint64_t aTransactionId,
+                                          const mozilla::TimeStamp& aTxnStartTime)
+{
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_ASSERT(mIsInTransaction);
+
+  TimeStamp fwdTime;
+#if defined(ENABLE_FRAME_LATENCY_LOG)
+  fwdTime = TimeStamp::Now();
+#endif
+
+  this->SendEmptyTransaction(aFocusTarget,
+                             mParentCommands, mDestroyedActors,
+                             GetFwdTransactionId(), aTransactionId,
+                             mIdNamespace, aTxnStartTime, fwdTime);
+  mParentCommands.Clear();
+  mDestroyedActors.Clear();
+  mIsInTransaction = false;
+}
+
 void
 WebRenderBridgeChild::ProcessWebRenderParentCommands()
 {

gfx/layers/wr/WebRenderBridgeChild.h

@@ -75,6 +75,9 @@ public:
                       bool aIsSync, uint64_t aTransactionId,
                       const WebRenderScrollData& aScrollData,
                       const mozilla::TimeStamp& aTxnStartTime);
+  void EndEmptyTransaction(const FocusTarget& aFocusTarget,
+                           uint64_t aTransactionId,
+                           const mozilla::TimeStamp& aTxnStartTime);
   void ProcessWebRenderParentCommands();
 
   CompositorBridgeChild* GetCompositorBridgeChild();

gfx/layers/wr/WebRenderBridgeParent.cpp

@@ -614,6 +614,48 @@ WebRenderBridgeParent::RecvSetDisplayListSync(const gfx::IntSize &aSize,
                             aIdNamespace, aTxnStartTime, aFwdTime);
 }
 
+mozilla::ipc::IPCResult
+WebRenderBridgeParent::RecvEmptyTransaction(const FocusTarget& aFocusTarget,
+                                            InfallibleTArray<WebRenderParentCommand>&& aCommands,
+                                            InfallibleTArray<OpDestroy>&& aToDestroy,
+                                            const uint64_t& aFwdTransactionId,
+                                            const uint64_t& aTransactionId,
+                                            const wr::IdNamespace& aIdNamespace,
+                                            const TimeStamp& aTxnStartTime,
+                                            const TimeStamp& aFwdTime)
+{
+  if (mDestroyed) {
+    for (const auto& op : aToDestroy) {
+      DestroyActor(op);
+    }
+    return IPC_OK();
+  }
+
+  AutoProfilerTracing tracing("Paint", "EmptyTransaction");
+  UpdateFwdTransactionId(aFwdTransactionId);
+  AutoClearReadLocks clearLocks(mReadLocks);
+
+  // This ensures that destroy operations are always processed. It is not safe
+  // to early-return without doing so.
+  AutoWebRenderBridgeParentAsyncMessageSender autoAsyncMessageSender(this, &aToDestroy);
+
+  if (!aCommands.IsEmpty()) {
+    mAsyncImageManager->SetCompositionTime(TimeStamp::Now());
+    ProcessWebRenderParentCommands(aCommands);
+    mCompositorScheduler->ScheduleComposition();
+  }
+
+  mScrollData.SetFocusTarget(aFocusTarget);
+  UpdateAPZ(false);
+
+  // XXX Call DidComposite at correct timing.
+  TimeStamp now = TimeStamp::Now();
+  HoldPendingTransactionId(mWrEpoch, aTransactionId, aTxnStartTime, aFwdTime);
+  mCompositorBridge->DidComposite(wr::AsUint64(mPipelineId), now, now);
+
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult
 WebRenderBridgeParent::RecvSetFocusTarget(const FocusTarget& aFocusTarget)
 {

gfx/layers/wr/WebRenderBridgeParent.h

@@ -106,6 +106,14 @@ public:
                                                  const wr::IdNamespace& aIdNamespace,
                                                  const TimeStamp& aTxnStartTime,
                                                  const TimeStamp& aFwdTime) override;
+  mozilla::ipc::IPCResult RecvEmptyTransaction(const FocusTarget& aFocusTarget,
+                                               InfallibleTArray<WebRenderParentCommand>&& aCommands,
+                                               InfallibleTArray<OpDestroy>&& aToDestroy,
+                                               const uint64_t& aFwdTransactionId,
+                                               const uint64_t& aTransactionId,
+                                               const wr::IdNamespace& aIdNamespace,
+                                               const TimeStamp& aTxnStartTime,
+                                               const TimeStamp& aFwdTime) override;
   mozilla::ipc::IPCResult RecvSetFocusTarget(const FocusTarget& aFocusTarget) override;
   mozilla::ipc::IPCResult RecvParentCommands(nsTArray<WebRenderParentCommand>&& commands) override;
   mozilla::ipc::IPCResult RecvGetSnapshot(PTextureParent* aTexture) override;

gfx/layers/wr/WebRenderCommandBuilder.cpp

@@ -31,6 +31,17 @@ void WebRenderCommandBuilder::Destroy()
   RemoveUnusedAndResetWebRenderUserData();
 }
 
+void
+WebRenderCommandBuilder::EmptyTransaction()
+{
+  // We need to update canvases that might have changed.
+  for (auto iter = mLastCanvasDatas.Iter(); !iter.Done(); iter.Next()) {
+    RefPtr<WebRenderCanvasData> canvasData = iter.Get()->GetKey();
+    WebRenderCanvasRendererAsync* canvas = canvasData->GetCanvasRenderer();
+    canvas->UpdateCompositableClient();
+  }
+}
+
 void
 WebRenderCommandBuilder::BuildWebRenderCommands(wr::DisplayListBuilder& aBuilder,
                                                 wr::IpcResourceUpdateQueue& aResourceUpdates,

gfx/layers/wr/WebRenderCommandBuilder.h

@@ -40,6 +40,8 @@ public:
 
   void Destroy();
 
+  void EmptyTransaction();
+
   void BuildWebRenderCommands(wr::DisplayListBuilder& aBuilder,
                               wr::IpcResourceUpdateQueue& aResourceUpdates,
                               nsDisplayList* aDisplayList,

gfx/layers/wr/WebRenderLayerManager.cpp

@@ -174,25 +174,35 @@ WebRenderLayerManager::BeginTransaction()
 bool
 WebRenderLayerManager::EndEmptyTransaction(EndTransactionFlags aFlags)
 {
+  LayoutDeviceIntSize size = mWidget->GetClientSize();
+  WrBridge()->BeginTransaction();
+
   // With the WebRenderLayerManager we reject attempts to set most kind of
   // "pending data" for empty transactions. Any place that attempts to update
   // transforms or scroll offset, for example, will get failure return values
   // back, and will fall back to a full transaction. Therefore the only piece
-  // of "pending" information we need to send in an empty transaction is the
-  // APZ focus state.
-  WrBridge()->SendSetFocusTarget(mFocusTarget);
+  // of "pending" information we need to send in an empty transaction are the
+  // APZ focus state and canvases's CompositableOperations.
 
-  // We also need to update canvases that might have changed, but this code
-  // as-is causes crashes so comment it out for now.
-  //for (auto iter = mLastCanvasDatas.Iter(); !iter.Done(); iter.Next()) {
-  //  RefPtr<WebRenderCanvasData> canvasData = iter.Get()->GetKey();
-  //  WebRenderCanvasRendererAsync* canvas = canvasData->GetCanvasRenderer();
-  //  canvas->UpdateCompositableClient();
-  //}
+  mWebRenderCommandBuilder.EmptyTransaction();
 
-  if (!(aFlags & EndTransactionFlags::END_NO_COMPOSITE)) {
-    ScheduleComposite();
+  WrBridge()->ClearReadLocks();
+
+  mLatestTransactionId = mTransactionIdAllocator->GetTransactionId(/*aThrottle*/ true);
+  TimeStamp transactionStart = mTransactionIdAllocator->GetTransactionStart();
+
+  // Skip the synchronization for buffer since we also skip the painting during
+  // device-reset status.
+  if (!gfxPlatform::GetPlatform()->DidRenderingDeviceReset()) {
+    if (WrBridge()->GetSyncObject() &&
+        WrBridge()->GetSyncObject()->IsSyncObjectValid()) {
+      WrBridge()->GetSyncObject()->Synchronize();
+    }
   }
+
+  WrBridge()->EndEmptyTransaction(mFocusTarget, mLatestTransactionId, transactionStart);
+
+  MakeSnapshotIfRequired(size);
   return true;
 }