Bug 1362889 - Ensure the MockContentController in APZ GTests doesn't outlive the test fixture. r=kats

MozReview-Commit-ID: AuSC5w1FXWG

--HG--
extra : rebase_source : 809bc22c63d6a3e16357eebf686b03442e189df5

gfx/layers/apz/test/gtest/APZCBasicTester.h

@@ -50,6 +50,7 @@ protected:
     while (mcc->RunThroughDelayedTasks());
     apzc->Destroy();
     tm->ClearTree();
+    tm->ClearContentController();
   }
 
   void MakeApzcWaitForMainThread()

gfx/layers/apz/test/gtest/APZCTreeManagerTester.h

@@ -30,6 +30,7 @@ protected:
   virtual void TearDown() {
     while (mcc->RunThroughDelayedTasks());
     manager->ClearTree();
+    manager->ClearContentController();
   }
 
   /**

gfx/layers/apz/test/gtest/APZTestCommon.h

@@ -176,6 +176,10 @@ public:
     return mInputQueue;
   }
 
+  void ClearContentController() {
+    mcc = nullptr;
+  }
+
 protected:
   AsyncPanZoomController* NewAPZCInstance(uint64_t aLayersId,
                                           GeckoContentController* aController) override;