Update IPC ParamTraits for SkBitmap to follow best practices.

Using memcpy() to serialize a POD struct is highly discouraged. Just use
the standard IPC param traits macros for doing it.

Bug: 779428
Change-Id: I48f52c1f5c245ba274d595829ed92e8b3cb41334
Reviewed-on: https://chromium-review.googlesource.com/899649
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534562}
 void ParamTraits<SkBitmap>::Write(base::Pickle* m, const SkBitmap& p) {
  WriteParam(m, p.info());
   size_t pixel_size = p.computeByteSize();
   m->WriteData(reinterpret_cast<const char*>(p.getPixels()),
                static_cast<int>(pixel_size));
}

 void ParamTraits<SkBitmap>::Write(base::Pickle* m, const SkBitmap& p) {
  size_t fixed_size = sizeof(SkBitmap_Data);
  SkBitmap_Data bmp_data;
  bmp_data.InitSkBitmapDataForTransfer(p);
  m->WriteData(reinterpret_cast<const char*>(&bmp_data),
               static_cast<int>(fixed_size));
   size_t pixel_size = p.computeByteSize();
   m->WriteData(reinterpret_cast<const char*>(p.getPixels()),
                static_cast<int>(pixel_size));
}
