Implement CompositorCC::ReadPixels

ui/gfx/compositor/compositor.cc

Index: ui/gfx/compositor/compositor.cc
diff --git a/ui/gfx/compositor/compositor.cc b/ui/gfx/compositor/compositor.cc
index 388d7d9196ba5b9df39f125fb85bcb6329757adf..6e9e1d5e216b3d92af98142906cbcfe7fe3af7a6 100644
--- a/ui/gfx/compositor/compositor.cc
+++ b/ui/gfx/compositor/compositor.cc
@@ -68,6 +68,29 @@ void Compositor::DrawTree() {
   root_layer_->DrawTree();
 }
 
+void Compositor::SwizzleRGBAToBGRAAndFlip(unsigned char* pixels,
+                                          const gfx::Size& image_size) {
+  // Swizzle from RGBA to BGRA
+  size_t bitmap_size = 4 * image_size.width() * image_size.height();
+  for(size_t i = 0; i < bitmap_size; i += 4)
+    std::swap(pixels[i], pixels[i + 2]);
+
+  // Vertical flip to transform from GL co-ords
+  size_t row_size = 4 * image_size.width();
+  scoped_array<unsigned char> tmp_row(new unsigned char[row_size]);
+  for(int row = 0; row < image_size.height() / 2; row++) {
+    memcpy(tmp_row.get(),
+           &pixels[row * row_size],
+           row_size);
+    memcpy(&pixels[row * row_size],
+           &pixels[bitmap_size - (row + 1) * row_size],
+           row_size);
+    memcpy(&pixels[bitmap_size - (row + 1) * row_size],
+           tmp_row.get(),
+           row_size);
+  }
+}
+
 void Compositor::NotifyStart(bool clear) {
   OnNotifyStart(clear);
 }