use SkPixmap inside sprite blitters

src/core/SkBlitter_Sprite.cpp

 /*
  * 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.
  */
 
 #include "SkSmallAllocator.h"
 #include "SkSpriteBlitter.h"
 
-SkSpriteBlitter::SkSpriteBlitter(const SkBitmap& source)
-        : fSource(&source) {
-    fSource->lockPixels();
+SkSpriteBlitter::SkSpriteBlitter(const SkBitmap& source) : fSource(NULL) {
+    if (source.requestLock(&fUnlocker)) {
+        fSource = &fUnlocker.pixmap();
+    }
 }
 
-SkSpriteBlitter::~SkSpriteBlitter() {
-    fSource->unlockPixels();
-}
-
-void SkSpriteBlitter::setup(const SkBitmap& device, int left, int top,
-                            const SkPaint& paint) {
+bool SkSpriteBlitter::setup(const SkBitmap& device, int left, int top, const SkPaint& paint) {
+    if (NULL == fSource) {
+        return false;
+    }
     fDevice = &device;
     fLeft = left;
     fTop = top;
     fPaint = &paint;
+    return true;
 }
 
 #ifdef SK_DEBUG
 void SkSpriteBlitter::blitH(int x, int y, int width) {
     SkDEBUGFAIL("how did we get here?");
 }
 
 void SkSpriteBlitter::blitAntiH(int x, int y, const SkAlpha antialias[],
                                 const int16_t runs[]) {
     SkDEBUGFAIL("how did we get here?");
@@ skipping 33 matching lines @@
             break;
         case kN32_SkColorType:
             blitter = SkSpriteBlitter::ChooseD32(source, paint, allocator);
             break;
         default:
             blitter = NULL;
             break;
     }
 
     if (blitter) {
-        blitter->setup(device, left, top, paint);
+        if (!blitter->setup(device, left, top, paint)) {
+            // blitter was allocated by allocator, so we have to manually call its destructor
+            blitter->~SkSpriteBlitter();
+            blitter = NULL;
+        }
     }
     return blitter;
 }