Bug 1298980 - Initialize AsyncPanZoomController global state in GPU Process. r=kats

MozReview-Commit-ID: EjDgxzF5HmZ

--HG--
extra : rebase_source : 79cb8dd3b0a6de115d9cb8126b56ca9e6053f8d4

gfx/ipc/GPUParent.cpp

@@ -12,6 +12,7 @@
 #include "mozilla/gfx/gfxVars.h"
 #include "mozilla/ipc/ProcessChild.h"
 #include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/APZCTreeManager.h"
 #include "mozilla/layers/CompositorBridgeParent.h"
 #include "mozilla/layers/CompositorThread.h"
 #include "mozilla/layers/ImageBridgeParent.h"
@@ -65,6 +66,7 @@ GPUParent::Init(base::ProcessId aParentPid,
   }
   CompositorThreadHolder::Start();
   APZThreadUtils::SetControllerThread(CompositorThreadHolder::Loop());
+  APZCTreeManager::InitializeGlobalState();
   VRManager::ManagerInit();
   LayerTreeOwnerTracker::Initialize();
   mozilla::ipc::SetThisProcessName("GPU Process");

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -100,7 +100,6 @@ APZCTreeManager::APZCTreeManager()
       mRetainedTouchIdentifier(-1),
       mApzcTreeLog("apzctree")
 {
-  MOZ_ASSERT(NS_IsMainThread());
   AsyncPanZoomController::InitializeGlobalState();
   mApzcTreeLog.ConditionOnPrefFunction(gfxPrefs::APZPrintTree);
 }
@@ -109,6 +108,13 @@ APZCTreeManager::~APZCTreeManager()
 {
 }
 
+/*static*/ void
+APZCTreeManager::InitializeGlobalState()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AsyncPanZoomController::InitializeGlobalState();
+}
+
 AsyncPanZoomController*
 APZCTreeManager::NewAPZCInstance(uint64_t aLayersId,
                                  GeckoContentController* aController)

gfx/layers/apz/src/APZCTreeManager.h

@@ -92,6 +92,14 @@ class APZCTreeManager : public IAPZCTreeManager {
 public:
   APZCTreeManager();
 
+  /**
+   * Initializes the global state used in AsyncPanZoomController.
+   * This is normally called when it is first needed in the constructor
+   * of APZCTreeManager, but can be called manually to force it to be
+   * initialized earlier.
+   */
+  static void InitializeGlobalState();
+
   /**
    * Rebuild the hit-testing tree based on the layer update that just came up.
    * Preserve nodes and APZC instances where possible, but retire those whose

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -659,13 +659,13 @@ private:
 /*static*/ void
 AsyncPanZoomController::InitializeGlobalState()
 {
-  MOZ_ASSERT(NS_IsMainThread());
-
   static bool sInitialized = false;
   if (sInitialized)
     return;
   sInitialized = true;
 
+  MOZ_ASSERT(NS_IsMainThread());
+
   gZoomAnimationFunction = new ComputedTimingFunction();
   gZoomAnimationFunction->Init(
     nsTimingFunction(NS_STYLE_TRANSITION_TIMING_FUNCTION_EASE));