From 9699c6d4db8344f3469941f3780655bc9fe3040f Mon Sep 17 00:00:00 2001
From: Nicolas Silva <nsilva@mozilla.com>
Date: Tue, 11 Sep 2018 16:50:48 +0200
Subject: [PATCH] Bug 1352877 - Clear the compositor map later during shutdown.
 r=mattwoodrow

---
 gfx/layers/ipc/CompositorBridgeParent.cpp | 15 +++++++--------
 gfx/layers/ipc/CompositorBridgeParent.h   |  7 +------
 gfx/layers/ipc/CompositorThread.cpp       |  1 -
 3 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/gfx/layers/ipc/CompositorBridgeParent.cpp b/gfx/layers/ipc/CompositorBridgeParent.cpp
index 816564fc33c4..be4b51cc3e33 100644
--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -313,17 +313,16 @@ CompositorBridgeParent::Setup()
   sCompositorMap = new CompositorMap;
 }
 
-void
-CompositorBridgeParent::Shutdown()
-{
-  MOZ_ASSERT(sCompositorMap);
-  MOZ_ASSERT(sCompositorMap->empty());
-  sCompositorMap = nullptr;
-}
-
 void
 CompositorBridgeParent::FinishShutdown()
 {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (sCompositorMap) {
+    MOZ_ASSERT(sCompositorMap->empty());
+    sCompositorMap = nullptr;
+  }
+
   // TODO: this should be empty by now...
   sIndirectLayerTrees.clear();
 }
diff --git a/gfx/layers/ipc/CompositorBridgeParent.h b/gfx/layers/ipc/CompositorBridgeParent.h
index 6e127542d62f..e0fa44d746b0 100644
--- a/gfx/layers/ipc/CompositorBridgeParent.h
+++ b/gfx/layers/ipc/CompositorBridgeParent.h
@@ -576,12 +576,7 @@ protected:
   static void Setup();
 
   /**
-   * Destroys the compositor thread and global compositor map.
-   */
-  static void Shutdown();
-
-  /**
-   * Finish the shutdown operation on the compositor thread.
+   * Remaning cleanups after the compositore thread is gone.
    */
   static void FinishShutdown();
 
diff --git a/gfx/layers/ipc/CompositorThread.cpp b/gfx/layers/ipc/CompositorThread.cpp
index 326988fc525d..c42e8b848dbe 100644
--- a/gfx/layers/ipc/CompositorThread.cpp
+++ b/gfx/layers/ipc/CompositorThread.cpp
@@ -69,7 +69,6 @@ CompositorThreadHolder::DestroyCompositorThread(base::Thread* aCompositorThread)
 
   MOZ_ASSERT(!sCompositorThreadHolder, "We shouldn't be destroying the compositor thread yet.");
 
-  CompositorBridgeParent::Shutdown();
   delete aCompositorThread;
   sFinishedCompositorShutDown = true;
 }