revert 6798 (assert in GM)

git-svn-id: http://skia.googlecode.com/svn/trunk@6802 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 10 insertions, 19 deletions

diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index 7edbe6fd4b..1286177271 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -139,29 +139,12 @@ public:
     /**
      *  Called once before drawing, with the current paint and device matrix.
      *  Return true if your shader supports these parameters, or false if not.
-     *  If false is returned, nothing will be drawn. If true is returned, then
-     *  a balancing call to endContext() will be made before the next call to
-     *  setContext.
-     *
-     *  Subclasses should be sure to call their INHERITED::setContext() if they
-     *  override this method.
+     *  If false is returned, nothing will be drawn.
      */
     virtual bool setContext(const SkBitmap& device, const SkPaint& paint,
                             const SkMatrix& matrix);
 
     /**
-     *  Assuming setContext returned true, endContext() will be called when
-     *  the draw using the shader has completed. It is an error for setContext
-     *  to be called twice w/o an intervening call to endContext().
-     *
-     *  Subclasses should be sure to call their INHERITED::endContext() if they
-     *  override this method.
-     */
-    virtual void endContext();
-
-    SkDEBUGCODE(bool setContextHasBeenCalled() const { return fInSetContext; })
-
-    /**
      *  Called for each span of the object being drawn. Your subclass should
      *  set the appropriate colors (with premultiplied alpha) that correspond
      *  to the specified device coordinates.
@@ -200,6 +183,14 @@ public:
     }
 
     /**
+     *  Called before a session using the shader begins. Some shaders override
+     *  this to defer some of their work (like calling bitmap.lockPixels()).
+     *  Must be balanced by a call to endSession.
+     */
+    virtual void beginSession();
+    virtual void endSession();
+
+    /**
      Gives method bitmap should be read to implement a shader.
      Also determines number and interpretation of "extra" parameters returned
      by asABitmap
@@ -364,7 +355,7 @@ private:
     uint8_t             fPaintAlpha;
     uint8_t             fDeviceConfig;
     uint8_t             fTotalInverseClass;
-    SkDEBUGCODE(SkBool8 fInSetContext;)
+    SkDEBUGCODE(SkBool8 fInSession;)
 
     static SkShader* CreateBitmapShader(const SkBitmap& src,
                                         TileMode, TileMode,