Picture Recording: fix the performance bottleneck in SkDeferredCanvas::isFullFrame

include/utils/SkDeferredCanvas.h

Index: include/utils/SkDeferredCanvas.h
diff --git a/include/utils/SkDeferredCanvas.h b/include/utils/SkDeferredCanvas.h
index 907cb91575043b1cfba2f16c1b27e4d6982c0516..35e6d6f55bd6e5759d81b912dfa5fc07a36fe2fe 100644
--- a/include/utils/SkDeferredCanvas.h
+++ b/include/utils/SkDeferredCanvas.h
@@ -89,6 +89,11 @@ public:
     bool isFreshFrame() const;
 
     /**
+     * Returns canvas's size.
+     */
+    SkISize getCanvasSize();
+
+    /**
      *  Returns true if the canvas has recorded draw commands that have
      *  not yet been played back.
      */
@@ -243,12 +248,14 @@ private:
     void recordedDrawCommand();
     SkCanvas* drawingCanvas() const;
     SkCanvas* immediateCanvas() const;
-    bool isFullFrame(const SkRect*, const SkPaint*) const;
+    bool isFullFrame(const SkRect*, const SkPaint*);
     void validate() const;
     void init();
 
-    size_t fBitmapSizeThreshold;
-    bool   fDeferredDrawing;
+    size_t  fBitmapSizeThreshold;
+    bool    fDeferredDrawing;
+    bool    fCanvasSizeChanged;
+    SkISize fCanvasSize;
 
     friend class SkDeferredCanvasTester; // for unit testing
     typedef SkCanvas INHERITED;