Add getReducedClipStack to lua canvas

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index e639212e384b0f58dda00b3e8086cbe03a059688..e9d4933d177112fed795e36746e3d482e414d4a8 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -90,12 +90,16 @@ public:
     void flush();
 
     /**
-     *  DEPRECATED: call imageInfo() instead.
-     *  Return the width/height of the underlying device. The current drawable
-     *  area may be small (due to clipping or saveLayer). For a canvas with
-     *  no device, 0,0 will be returned.
+     * Gets the size of the base or root layer in global canvas coordinates. The
+     * origin of the base layer is always (0,0). The current drawable area may be
+     * smaller (due to clipping or saveLayer).
      */
-    SkISize getDeviceSize() const;
+    SkISize getBaseLayerSize() const;
+
+    /**
+     *  DEPRECATED: call getBaseLayerSize
+     */
+    SkISize getDeviceSize() const { return this->getBaseLayerSize(); }
 
     /**
      *  DEPRECATED.
@@ -1129,6 +1133,7 @@ private:
 
     friend class SkDrawIter;    // needs setupDrawForLayerDevice()
     friend class AutoDrawLooper;
+    friend class SkLua;         // needs top layer size and offset
 
     SkBaseDevice* createLayerDevice(const SkImageInfo&);
 
@@ -1143,6 +1148,12 @@ private:
      */
     SkBaseDevice* setRootDevice(SkBaseDevice* device);
 
+    /**
+     * Gets the size/origin of the top level layer in global canvas coordinates. We don't want this
+     * to be public because it exposes decisions about layer sizes that are internal to the canvas.
+     */
+    SkISize getTopLayerSize() const;
+    SkIPoint getTopLayerOrigin() const;
 
     // internal methods are not virtual, so they can safely be called by other
     // canvas apis, without confusing subclasses (like SkPictureRecording)