Fix alpha pre-multiplication error with custom cursor images

content/common/cursors/webcursor.cc

Index: content/common/cursors/webcursor.cc
diff --git a/content/common/cursors/webcursor.cc b/content/common/cursors/webcursor.cc
index 6bc3f3eb98fa7985262f2a056f10d399ccff798a..faa6d703b4f53169468556fe15d596ca0c1ad33e 100644
--- a/content/common/cursors/webcursor.cc
+++ b/content/common/cursors/webcursor.cc
@@ -231,10 +231,12 @@ void WebCursor::SetCustomData(const SkBitmap& bitmap) {
     return;
 
   // Fill custom_data_ directly with the NativeImage pixels.
-  SkAutoLockPixels bitmap_lock(bitmap);
   custom_data_.resize(bitmap.getSize());
-  if (!custom_data_.empty())
-    memcpy(&custom_data_[0], bitmap.getPixels(), bitmap.getSize());
+  if (!custom_data_.empty()) {
+    //This will divide color values by alpha (un-premultiply) if necessary
+    SkImageInfo dstInfo = bitmap.info().makeAlphaType(kUnpremul_SkAlphaType);
+    bitmap.readPixels(dstInfo, &custom_data_[0], dstInfo.minRowBytes(), 0, 0);
+  }
   custom_size_.set_width(bitmap.width());
   custom_size_.set_height(bitmap.height());
 }
@@ -243,7 +245,10 @@ void WebCursor::ImageFromCustomData(SkBitmap* image) const {
   if (custom_data_.empty())
     return;
 
-  if (!image->tryAllocN32Pixels(custom_size_.width(), custom_size_.height()))
+  SkImageInfo image_info = SkImageInfo::MakeN32(custom_size_.width(),
+                                                custom_size_.height(),
+                                                kUnpremul_SkAlphaType);
+  if (!image->tryAllocPixels(image_info))
     return;
   memcpy(image->getPixels(), &custom_data_[0], custom_data_.size());
 }