Revert[2] SkDraw and all Blitters to use pixmap instead of bitmapi

This reverts commit b3f0ec9f9967da2f80f0d842cb7fd53617b48de3.

BUG=skia:

Review URL: https://codereview.chromium.org/1168303006
diff --git a/src/effects/SkLayerRasterizer.cpp b/src/effects/SkLayerRasterizer.cpp
index d3e112c..8403d06 100644
--- a/src/effects/SkLayerRasterizer.cpp
+++ b/src/effects/SkLayerRasterizer.cpp
@@ -116,9 +116,12 @@
     }
 
     if (SkMask::kJustComputeBounds_CreateMode != mode) {
-        SkBitmap        device;
-        SkRasterClip    rectClip;
         SkDraw          draw;
+        if (!draw.fDst.reset(*mask)) {
+            return false;
+        }
+
+        SkRasterClip    rectClip;
         SkMatrix        translatedMatrix;  // this translates us to our local pixels
         SkMatrix        drawMatrix;        // this translates the path by each layer's offset
 
@@ -128,9 +131,6 @@
         translatedMatrix.postTranslate(-SkIntToScalar(mask->fBounds.fLeft),
                                        -SkIntToScalar(mask->fBounds.fTop));
 
-        device.installMaskPixels(*mask);
-
-        draw.fBitmap    = &device;
         draw.fMatrix    = &drawMatrix;
         draw.fRC        = &rectClip;
         draw.fClip      = &rectClip.bwRgn();