Add isUnblended query to GrDrawState.

src/gpu/GrDrawState.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawState_DEFINED
 #define GrDrawState_DEFINED
 
@@ skipping 141 matching lines @@
      * intends to specify fractional pixel coverage (via setCoverage(), through a coverage vertex
      * attribute, or a coverage effect) but may not have specified it yet.
      */
     bool couldApplyCoverage(const GrDrawTargetCaps& caps) const;
 
     /**
      * Determines whether the output coverage is guaranteed to be one for all pixels hit by a draw.
      */
     bool hasSolidCoverage() const;
 
+    /**
+     * Determines whether or not a draw will do any blending with the current draw state. For it to
+     * be unblended, it must have solid coverage, have final blend coeffs [1,0], and no effect can

[bsalomon, 2014/11/11 20:49:56]

Can we not document the implementation but rather the meaning to the caller?
Something like "If this returns true then the render target destination pixel
values will not be read for blending during the draw."

Maybe we should call it willBlendWithDst()? (Of course that'd reverse the
boolean sense of it.)

[egdaniel, 2014/11/11 21:05:55]

Done.

+     * readDst (otherwise custom blending will occur with in a fragment stage).
+     */
+    bool isUnblended() const;
+
     /// @}
 
     ///////////////////////////////////////////////////////////////////////////
     /// @name Color
     ////
 
     GrColor getColor() const { return fColor; }
 
     /**
      *  Sets color for next draw to a premultiplied-alpha color.
@@ skipping 661 matching lines @@
     int fFixedFunctionVertexAttribIndices[kGrFixedFunctionVertexAttribBindingCnt];
 
     friend class GrOptDrawState;
 
     typedef SkRefCnt INHERITED;
 };
 
 GR_MAKE_BITFIELD_OPS(GrDrawState::BlendOptFlags);
 
 #endif