Bug 1273075 - initialize |mPixelsPerFrame| and |mPixelsFilled|. r=jrmuizel

MozReview-Commit-ID: AzevXVRAZvM

--HG--
extra : rebase_source : 1d94ea2901db7aac43ec404deac923b4a587c096

gfx/layers/Compositor.h

@@ -195,6 +195,8 @@ public:
     : mCompositorID(0)
     , mDiagnosticTypes(DiagnosticTypes::NO_DIAGNOSTIC)
     , mParent(aParent)
+    , mPixelsPerFrame(0)
+    , mPixelsFilled(0)
     , mScreenRotation(ROTATION_0)
     , mWidget(aWidget)
   {