Revert of Revert of allow canvas to force conservative clips (for speed)

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index f514d18b5ee89e113a54035e7e5d9f8a7db9e59d..5088d7ded5268b9e86808c3c7d0148c7bcc891a4 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -1265,11 +1265,6 @@
                         SkIRect* intersection,
                         const SkImageFilter* imageFilter = NULL);
 
-    // Called by child classes that override clipPath and clipRRect to only
-    // track fast conservative clip bounds, rather than exact clips.
-    void updateClipConservativelyUsingBounds(const SkRect&, SkRegion::Op,
-                                             bool inverseFilled);
-
     // notify our surface (if we have one) that we are about to draw, so it
     // can perform copy-on-write or invalidate any cached images
     void predrawNotify();
@@ -1309,13 +1304,22 @@
     friend class SkDebugCanvas;     // needs experimental fAllowSimplifyClip
     friend class SkDeferredDevice;  // needs getTopDevice()
     friend class SkSurface_Raster;  // needs getDevice()
+    friend class SkRecorder;        // InitFlags
+    friend class SkNoSaveLayerCanvas;   // InitFlags
     
+    enum InitFlags {
+        kDefault_InitFlags                  = 0,
+        kConservativeRasterClip_InitFlag    = 1 << 0,
+    };
+    SkCanvas(int width, int height, InitFlags flags);
+    SkCanvas(SkBaseDevice*, InitFlags flags);
+
     // needs gettotalclip()
     friend SkCanvasState* SkCanvasStateUtils::CaptureCanvasState(SkCanvas*);
     
     SkBaseDevice* createLayerDevice(const SkImageInfo&);
 
-    SkBaseDevice* init(SkBaseDevice*);
+    SkBaseDevice* init(SkBaseDevice*, InitFlags);
 
     /**
      *  DEPRECATED
@@ -1365,6 +1369,7 @@
     mutable bool   fCachedLocalClipBoundsDirty;
     bool fAllowSoftClip;
     bool fAllowSimplifyClip;
+    bool fConservativeRasterClip;
 
     const SkRect& getLocalClipBounds() const {
         if (fCachedLocalClipBoundsDirty) {