Convert images sent back from the renderer on image decode requests

We assumed that giving an image to decode would result in an N32 pixel
format reply, but it seems not. So convert to N32 on receipt of the
reply from the renderer.

R=rsesek@chromium.org

Bug: 1148012, 1144462
Change-Id: I7ae2924f6450cb4d0261d6780861f85bf5ed15a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533519Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826576}

services/data_decoder/public/cpp/BUILD.gn

@@ -41,11 +41,12 @@ source_set("cpp") {
     "//base",
     "//services/data_decoder/public/mojom",
   ]
+  deps = []
 
   if (is_android) {
     sources += [ "json_sanitizer_android.cc" ]
 
-    deps =
+    deps +=
         [ "//services/data_decoder/public/cpp/android:safe_json_jni_headers" ]
   } else {
     sources += [ "json_sanitizer_non_android.cc" ]
@@ -65,6 +66,7 @@ source_set("cpp") {
       "decode_image.cc",
       "safe_web_bundle_parser.cc",
     ]
+    deps += [ "//skia" ]
   }
 
   defines = [ "IS_DATA_DECODER_PUBLIC_IMPL" ]

services/data_decoder/public/cpp/decode_image.cc

@@ -11,6 +11,7 @@
 #include "base/debug/dump_without_crashing.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "services/data_decoder/public/cpp/data_decoder.h"
+#include "skia/ext/skia_utils_base.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace data_decoder {
@@ -22,11 +23,13 @@ namespace {
 // which point the reply is forwarded to the wrapped |callback|.
 void OnDecodeImage(mojo::Remote<mojom::ImageDecoder> decoder,
                    mojom::ImageDecoder::DecodeImageCallback callback,
-                   const SkBitmap& bitmap) {
-  if (bitmap.colorType() != kN32_SkColorType) {
-    // The renderer should be sending us N32 32bpp bitmaps in reply, otherwise
-    // this can lead to out-of-bounds mistakes when transferring the pixels out
-    // of the bitmap into other buffers.
+                   const SkBitmap& unsafe_bitmap) {
+  // On receipt of an arbitrary bitmap from the renderer, we convert to an N32
+  // 32bpp bitmap. Other pixel sizes can lead to out-of-bounds mistakes when
+  // transferring the pixels out of the bitmap into other buffers.
+  SkBitmap bitmap;
+  if (!skia::SkBitmapToN32OpaqueOrPremul(unsafe_bitmap, &bitmap)) {
+    NOTREACHED() << "Unable to convert bitmap for decode image";
     base::debug::DumpWithoutCrashing();
     std::move(callback).Run(SkBitmap());
     return;