[cc] Show GPU memory usage and overage below FPS counter

cc/heads_up_display_layer_impl.h

Index: cc/heads_up_display_layer_impl.h
diff --git a/cc/heads_up_display_layer_impl.h b/cc/heads_up_display_layer_impl.h
index 6e5a30dd6e89acaf303677712c578b57aa5445a0..41ef8059e14f8d5a59f2b574bc39e2b4c8178aeb 100644
--- a/cc/heads_up_display_layer_impl.h
+++ b/cc/heads_up_display_layer_impl.h
@@ -21,6 +21,7 @@ namespace cc {
 class DebugRectHistory;
 class FontAtlas;
 class FrameRateCounter;
+class MemoryHistory;
 class PaintTimeCounter;
 
 class CC_EXPORT HeadsUpDisplayLayerImpl : public LayerImpl {
@@ -75,6 +76,7 @@ private:
     void drawGraphLines(SkCanvas*, SkPaint*, const SkRect& bounds, const Graph&);
 
     int drawFPSDisplay(SkCanvas*, FrameRateCounter*, const int& top);
+    int drawMemoryDisplay(SkCanvas*, MemoryHistory*, const int& top);
     int drawPaintTimeDisplay(SkCanvas*, PaintTimeCounter*, const int& top);
 
     void drawDebugRects(SkCanvas*, DebugRectHistory*);