Call GdiAlphaBlend directly instead of the AlphaBlend wrapper in msimg32.dll....

base/gfx/vector_device.cc

Index: base/gfx/vector_device.cc
===================================================================
--- base/gfx/vector_device.cc	(revision 3604)
+++ base/gfx/vector_device.cc	(working copy)
@@ -583,13 +583,13 @@
     DCHECK(result);
     // Note that this function expect premultiplied colors (!)
     BLENDFUNCTION blend_function = {AC_SRC_OVER, 0, alpha, AC_SRC_ALPHA};
-    result = AlphaBlend(dc,
-                        x, y,  // Destination origin.
-                        src_size_x, src_size_y,  // Destination size.
-                        bitmap_dc,
-                        0, 0,  // Source origin.
-                        src_size_x, src_size_y,  // Source size.
-                        blend_function);
+    result = GdiAlphaBlend(dc,
+                           x, y,  // Destination origin.
+                           src_size_x, src_size_y,  // Destination size.
+                           bitmap_dc,
+                           0, 0,  // Source origin.
+                           src_size_x, src_size_y,  // Source size.
+                           blend_function);
     DCHECK(result);
     result = SetStretchBltMode(dc, previous_mode);
     DCHECK(result);