Remove deferred clear from SkGpuDevice

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 106 matching lines @@
 
     /**
      *  Return ImageInfo for this canvas. If the canvas is not backed by pixels
      *  (cpu or gpu), then the info's ColorType will be kUnknown_SkColorType.
      */
     SkImageInfo imageInfo() const;
 
     ///////////////////////////////////////////////////////////////////////////
 
     /**
-     *  Trigger the immediate execution of all pending draw operations.
+     *  Trigger the immediate execution of all pending draw operations. For the GPU
+     *  backend this will resolve all rendering to the GPU surface backing the
+     *  SkSurface that owns this canvas.
      */
     void flush();
 
     /**
      * Gets the size of the base or root layer in global canvas coordinates. The
      * origin of the base layer is always (0,0). The current drawable area may be
      * smaller (due to clipping or saveLayer).
      */
     virtual SkISize getBaseLayerSize() const;
 
@@ skipping 1355 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif