Mash: Show app icons in shelf based on the Widget's app icon

components/mus/public/cpp/lib/property_type_converters.cc

Index: components/mus/public/cpp/lib/property_type_converters.cc
diff --git a/components/mus/public/cpp/lib/property_type_converters.cc b/components/mus/public/cpp/lib/property_type_converters.cc
index 2e1ff65818c014d568d7f3f3fddcd1b4bea7b94a..1fcf5c3488ca0d6099665ad8fe50fc83bd111e85 100644
--- a/components/mus/public/cpp/lib/property_type_converters.cc
+++ b/components/mus/public/cpp/lib/property_type_converters.cc
@@ -7,9 +7,17 @@
 #include <stdint.h>
 
 #include "base/strings/utf_string_conversions.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
+namespace {
+
+// Maximum height or width of a bitmap, in pixels.
+const int kMaxBitmapSize = 4096;

[msw, 2016/03/24 17:40:54]

Does this number come from somewhere else? Can we re-use a const? Otherwise, if
this is a semi-arbitrary limit, make the comment clearer. ('Maximum desired'?)

[James Cook, 2016/03/25 15:39:28]

Done.

+
+}  // namespace
+
 namespace mojo {
 
 // static
@@ -73,7 +81,7 @@ gfx::Size TypeConverter<gfx::Size, const std::vector<uint8_t>>::Convert(
 const std::vector<uint8_t>
     TypeConverter<const std::vector<uint8_t>, int32_t>::Convert(
         const int32_t& input) {
-  std::vector<uint8_t> vec(8);
+  std::vector<uint8_t> vec(4);

[msw, 2016/03/24 17:40:54]

Nice catch, but hopefully no callers relied on this; tough to check...

[James Cook, 2016/03/25 15:39:28]

I think it'll be OK. The deserialize is 4 bytes. We'll get an assertion failure
running in Debug if someone tries to use vector operator[] to read off the end
of this vector. If someone is directly accessing the bytes, well, they get what
they deserve. :-)

   vec[0] = (input >> 24) & 0xFF;
   vec[1] = (input >> 16) & 0xFF;
   vec[2] = (input >> 8) & 0xFF;
@@ -118,5 +126,77 @@ TypeConverter<std::string, const std::vector<uint8_t>>::Convert(
   return std::string(input.begin(), input.end());
 }
 
-}  // namespace mojo
+// static
+const std::vector<uint8_t>
+TypeConverter<const std::vector<uint8_t>, SkBitmap>::Convert(
+    const SkBitmap& input) {
+  // Empty images are valid to serialize and are represented by an empty vector.
+  if (input.isNull())
+    return std::vector<uint8_t>();
+
+  // Only RGBA 8888 bitmaps with premultiplied alpha are supported.
+  if (input.colorType() != kBGRA_8888_SkColorType ||
+      input.alphaType() != kPremul_SkAlphaType) {
+    NOTREACHED();
+    return std::vector<uint8_t>();
+  }
+
+  // Sanity check the bitmap size.
+  int width = input.width();
+  int height = input.height();
+  if (width < 0 || width > kMaxBitmapSize || height < 0 ||
+      height > kMaxBitmapSize) {
+    NOTREACHED();
+    return std::vector<uint8_t>();
+  }
+
+  // Serialize the bitmap.
+  std::vector<uint8_t> vec(8 + input.getSize());

[sky, 2016/03/23 23:30:40]

If you are only going to allow 4096, then you only need the last two bytes.

[James Cook, 2016/03/25 15:39:28]

Good catch. Done.

+  vec[0] = (width >> 24) & 0xFF;
+  vec[1] = (width >> 16) & 0xFF;
+  vec[2] = (width >> 8) & 0xFF;
+  vec[3] = width & 0xFF;
+  vec[4] = (height >> 24) & 0xFF;
+  vec[5] = (height >> 16) & 0xFF;
+  vec[6] = (height >> 8) & 0xFF;
+  vec[7] = height & 0xFF;
+  if (!input.copyPixelsTo(&vec[8], input.getSize()))
+    return std::vector<uint8_t>();
+  return vec;
+}
 
+// static
+SkBitmap TypeConverter<SkBitmap, const std::vector<uint8_t>>::Convert(
+    const std::vector<uint8_t>& input) {
+  // Empty images are represented by empty vectors.
+  if (input.empty())
+    return SkBitmap();
+
+  // Read and sanity check size.
+  int width = input[0] << 24 | input[1] << 16 | input[2] << 8 | input[3];
+  int height = input[4] << 24 | input[5] << 16 | input[6] << 8 | input[7];
+  if (width < 0 || width > kMaxBitmapSize || height < 0 ||
+      height > kMaxBitmapSize) {
+    NOTREACHED();
+    return SkBitmap();
+  }
+
+  // Try to allocate a bitmap of the appropriate size.
+  SkBitmap bitmap;
+  if (!bitmap.tryAllocPixels(SkImageInfo::Make(
+          width, height, kBGRA_8888_SkColorType, kPremul_SkAlphaType))) {
+    return SkBitmap();
+  }
+
+  // Ensure the vector contains the right amount of data.
+  if (input.size() != bitmap.getSize() + 8) {
+    NOTREACHED();
+    return SkBitmap();
+  }
+
+  // Read the pixel data.
+  memcpy(bitmap.getPixels(), &input[8], bitmap.getSize());
+  return bitmap;
+}
+
+}  // namespace mojo