From bf2bee5c8ee41f642f117fa0ffceb9ddb9fcddbb Mon Sep 17 00:00:00 2001
From: sotaro <sotaro.ikeda.g@gmail.com>
Date: Fri, 10 Aug 2018 08:10:11 +0900
Subject: [PATCH] Bug 1481995 - Remove WebRenderBridgeParent::mForceRendering
 r=nical

---
 gfx/layers/ipc/CompositorVsyncScheduler.cpp |  7 +++++++
 gfx/layers/ipc/CompositorVsyncScheduler.h   |  6 ++++++
 gfx/layers/wr/WebRenderBridgeParent.cpp     | 21 +++++++++++++--------
 gfx/layers/wr/WebRenderBridgeParent.h       |  3 ++-
 4 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/gfx/layers/ipc/CompositorVsyncScheduler.cpp b/gfx/layers/ipc/CompositorVsyncScheduler.cpp
index 38a4645c1b06..433ef91495ee 100644
--- a/gfx/layers/ipc/CompositorVsyncScheduler.cpp
+++ b/gfx/layers/ipc/CompositorVsyncScheduler.cpp
@@ -348,5 +348,12 @@ CompositorVsyncScheduler::GetLastComposeTime() const
   return mLastCompose;
 }
 
+void
+CompositorVsyncScheduler::UpdateLastComposeTime()
+{
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
+  mLastCompose = TimeStamp::Now();
+}
+
 } // namespace layers
 } // namespace mozilla
diff --git a/gfx/layers/ipc/CompositorVsyncScheduler.h b/gfx/layers/ipc/CompositorVsyncScheduler.h
index 4b24917b4412..a33b0cd6203d 100644
--- a/gfx/layers/ipc/CompositorVsyncScheduler.h
+++ b/gfx/layers/ipc/CompositorVsyncScheduler.h
@@ -93,6 +93,12 @@ public:
    */
   const TimeStamp& GetLastComposeTime() const;
 
+  /**
+   * Update LastCompose TimeStamp to current timestamp.
+   * The function is typically used when composition is handled outside the CompositorVsyncScheduler.
+   */
+  void UpdateLastComposeTime();
+
 private:
   virtual ~CompositorVsyncScheduler();
 
diff --git a/gfx/layers/wr/WebRenderBridgeParent.cpp b/gfx/layers/wr/WebRenderBridgeParent.cpp
index 9edb35bf25a9..2de86b5164bc 100644
--- a/gfx/layers/wr/WebRenderBridgeParent.cpp
+++ b/gfx/layers/wr/WebRenderBridgeParent.cpp
@@ -200,7 +200,6 @@ WebRenderBridgeParent::WebRenderBridgeParent(CompositorBridgeParentBase* aCompos
   , mIdNamespace(aApi->GetNamespace())
   , mPaused(false)
   , mDestroyed(false)
-  , mForceRendering(false)
   , mReceivedDisplayList(false)
 {
   MOZ_ASSERT(mAsyncImageManager);
@@ -221,7 +220,6 @@ WebRenderBridgeParent::WebRenderBridgeParent(const wr::PipelineId& aPipelineId)
   , mIdNamespace{0}
   , mPaused(false)
   , mDestroyed(true)
-  , mForceRendering(false)
   , mReceivedDisplayList(false)
 {
 }
@@ -1041,9 +1039,12 @@ WebRenderBridgeParent::FlushFrameGeneration()
 
   // This forces a new GenerateFrame transaction to be sent to the render
   // backend thread, if one is pending. This doesn't block on any other threads.
-  mForceRendering = true;
-  mCompositorScheduler->FlushPendingComposite();
-  mForceRendering = false;
+  if (mCompositorScheduler->NeedsComposite()) {
+    mCompositorScheduler->CancelCurrentCompositeTask();
+    // Update timestamp of scheduler for APZ and animation.
+    mCompositorScheduler->UpdateLastComposeTime();
+    MaybeGenerateFrame(/* aForceGenerateFrame */ true);
+  }
 }
 
 void
@@ -1497,14 +1498,18 @@ WebRenderBridgeParent::CompositeToTarget(gfx::DrawTarget* aTarget, const gfx::In
     return;
   }
 
-  if (!mForceRendering &&
-      wr::RenderThread::Get()->TooManyPendingFrames(mApi->GetId())) {
+  if (wr::RenderThread::Get()->TooManyPendingFrames(mApi->GetId())) {
     // Render thread is busy, try next time.
     mCompositorScheduler->ScheduleComposition();
     mPreviousFrameTimeStamp = TimeStamp();
     return;
   }
+  MaybeGenerateFrame(/* aForceGenerateFrame */ false);
+}
 
+void
+WebRenderBridgeParent::MaybeGenerateFrame(bool aForceGenerateFrame)
+{
   TimeStamp start = TimeStamp::Now();
   mAsyncImageManager->SetCompositionTime(start);
 
@@ -1531,7 +1536,7 @@ WebRenderBridgeParent::CompositeToTarget(gfx::DrawTarget* aTarget, const gfx::In
 
   if (!mAsyncImageManager->GetAndResetWillGenerateFrame() &&
       fastTxn.IsEmpty() &&
-      !mForceRendering) {
+      !aForceGenerateFrame) {
     // Could skip generating frame now.
     mPreviousFrameTimeStamp = TimeStamp();
     return;
diff --git a/gfx/layers/wr/WebRenderBridgeParent.h b/gfx/layers/wr/WebRenderBridgeParent.h
index f5ff8eeb2091..8f18d9d9af95 100644
--- a/gfx/layers/wr/WebRenderBridgeParent.h
+++ b/gfx/layers/wr/WebRenderBridgeParent.h
@@ -252,6 +252,8 @@ private:
   void FlushFrameGeneration();
   void FlushFramePresentation();
 
+  void MaybeGenerateFrame(bool aForceGenerateFrame);
+
 private:
   struct PendingTransactionId {
     PendingTransactionId(const wr::Epoch& aEpoch,
@@ -313,7 +315,6 @@ private:
 
   bool mPaused;
   bool mDestroyed;
-  bool mForceRendering;
   bool mReceivedDisplayList;
 };