Ensure gfxPlatform is created before creating a compositor on Android. (bug 1254899 part 3.1, r=snorp)

widget/android/nsWindow.cpp

@@ -1783,6 +1783,9 @@ nsWindow::CreateLayerManager(int aCompositorWidth, int aCompositorHeight)
         return;
     }
 
+    // Ensure that gfxPlatform is initialized first.
+    gfxPlatform::GetPlatform();
+
     if (ShouldUseOffMainThreadCompositing()) {
         CreateCompositor(aCompositorWidth, aCompositorHeight);
         if (mLayerManager) {