Add cull rect visualization to debugger

src/utils/debugger/SkDebugCanvas.h

Index: src/utils/debugger/SkDebugCanvas.h
===================================================================
--- src/utils/debugger/SkDebugCanvas.h	(revision 13645)
+++ src/utils/debugger/SkDebugCanvas.h	(working copy)
@@ -254,7 +254,7 @@
     virtual void onClipPath(const SkPath&, SkRegion::Op, ClipEdgeStyle) SK_OVERRIDE;
     virtual void onClipRegion(const SkRegion& region, SkRegion::Op) SK_OVERRIDE;
 
-    void markActiveSaveLayers(int index);
+    void markActiveCommands(int index);
 
 private:
     SkTDArray<SkDrawCommand*> fCommandVector;
@@ -281,6 +281,18 @@
     */
     int fOutstandingSaveCount;
 
+    /** 
+        The active saveLayer commands at a given point in the renderering.
+        Only used when "mega" visualization is enabled.
+    */
+    SkTDArray<SkDrawCommand*> fActiveLayers;
+
+    /** 
+        The active cull commands at a given point in the rendering.
+        Only used when "mega" visualization is enabled.
+    */
+    SkTDArray<SkDrawCommand*> fActiveCulls;
+
     /**
         Adds the command to the classes vector of commands.
         @param command  The draw command for execution