Implement the clip as 4 or fewer GrEffects when possible.

src/gpu/GrClipMaskManager.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrClipMaskManager_DEFINED
 #define GrClipMaskManager_DEFINED
 
@@ skipping 87 matching lines @@
      * haven't yet examined the clip.
      */
     enum ClipMaskType {
         kNone_ClipMaskType,
         kStencil_ClipMaskType,
         kAlpha_ClipMaskType,
     } fCurrClipMaskType;
 
     GrClipMaskCache fAACache;       // cache for the AA path
 
+    // Attempts to install a series of coverage effects to implement the clip. Return indicates
+    // whether the element list was successfully converted to effects.
+    bool installClipEffects(const GrReducedClip::ElementList&,
+                            GrDrawState::AutoRestoreEffects*,
+                            const SkVector& clipOffset,
+                            const SkRect* devBounds);
+
     // Draws the clip into the stencil buffer
     bool createStencilClipMask(int32_t elementsGenID,
                                GrReducedClip::InitialState initialState,
                                const GrReducedClip::ElementList& elements,
                                const SkIRect& clipSpaceIBounds,
                                const SkIPoint& clipSpaceToStencilOffset);
     // Creates an alpha mask of the clip. The mask is a rasterization of elements through the
     // rect specified by clipSpaceIBounds.
     GrTexture* createAlphaClipMask(int32_t elementsGenID,
                                    GrReducedClip::InitialState initialState,
@@ skipping 48 matching lines @@
      * clipping.
      */
     void adjustStencilParams(GrStencilSettings* settings,
                              StencilClipMode mode,
                              int stencilBitCnt);
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif // GrClipMaskManager_DEFINED