change SkDraw and all Blitters to use pixmap instead of bitmap

src/utils/SkTextureCompressor_Blitter.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTextureCompressor_Blitter_DEFINED
 #define SkTextureCompressor_Blitter_DEFINED
 
@@ skipping 350 matching lines @@
                 }
 
                 dst += EncodedBlockSize;
             }
         }
     }
 
     // If the blitter just sets a single value for each pixel, return the
     // bitmap it draws into, and assign value. If not, return NULL and ignore
     // the value parameter.
-    const SkBitmap* justAnOpaqueColor(uint32_t* value) override {
+    const SkPixmap* justAnOpaqueColor(uint32_t* value) override {
         return NULL;
     }
 
     /**
      * Compressed texture blitters only really work correctly if they get
      * BlockDim rows at a time. That being said, this blitter tries it's best
      * to preserve semantics if blitAntiH doesn't get called in too many
      * weird ways...
      */
     int requestRowsPreserved() const override { return BlockDim; }
@@ skipping 342 matching lines @@
                                         mask, BlockDim, mask);
         }
     }
 #endif  // PEDANTIC_BLIT_RECT
 
 };
 
 }  // namespace SkTextureCompressor
 
 #endif  // SkTextureCompressor_Blitter_DEFINED