Revert "Revert of https://codereview.chromium.org/129423002/"

src/core/SkBitmap.cpp

 
 /*
  * Copyright 2008 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 "SkBitmap.h"
@@ skipping 315 matching lines @@
 }
 
 bool SkBitmap::setAlphaType(SkAlphaType alphaType) {
     if (!validate_alphaType(this->config(), alphaType, &alphaType)) {
         return false;
     }
     fAlphaType = SkToU8(alphaType);
     return true;
 }
 
+SkPixelRef* SkBitmap::installPixelRef(SkPixelRef* pr, const SkIRect* subset) {
+    if (NULL == pr) {
+        this->reset();
+        return NULL;
+    }
+
+    const SkImageInfo& info = pr->info();
+
+    fConfig = SkColorTypeToBitmapConfig(info.fColorType);
+    fAlphaType = info.fAlphaType;
+    fBytesPerPixel = info.bytesPerPixel();
+    // not known until we're locked
+    fRowBytes = 0;
+    
+    SkIRect bounds = { 0, 0, info.fWidth, info.fHeight };
+    if (subset && !bounds.intersect(*subset)) {
+        bounds.setEmpty();
+    }
+
+    fWidth = bounds.width();
+    fHeight = bounds.height();
+    return this->setPixelRef(pr, bounds.left(), bounds.top());
+}
+
 void SkBitmap::updatePixelsFromRef() const {
     if (NULL != fPixelRef) {
         if (fPixelLockCount > 0) {
             SkASSERT(fPixelRef->isLocked());
 
             void* p = fPixelRef->pixels();
             if (NULL != p) {
                 p = (char*)p
                     + fPixelRefOrigin.fY * fRowBytes
                     + fPixelRefOrigin.fX * fBytesPerPixel;
@@ skipping 1290 matching lines @@
         if (NULL != uri) {
             str->appendf(" uri:\"%s\"", uri);
         } else {
             str->appendf(" pixelref:%p", pr);
         }
     }
 
     str->append(")");
 }
 #endif