LibVideo/VP9: Use unit conversion functions in BlockContext

This should make things in there seem a little less magical :^)

Userland/Libraries/LibVideo/VP9/Context.h

@@ -69,14 +69,14 @@ public:
         m_size = size;
 
         // From spec, compute_image_size( )
-        m_rows = (size.height() + 7u) >> 3u;
-        m_columns = (size.width() + 7u) >> 3u;
+        m_rows = pixels_to_blocks(size.height() + 7u);
+        m_columns = pixels_to_blocks(size.width() + 7u);
         return m_block_contexts.try_resize(m_rows, m_columns);
     }
     u32 rows() const { return m_rows; }
     u32 columns() const { return m_columns; }
-    u32 superblock_rows() const { return (rows() + 7u) >> 3u; }
-    u32 superblock_columns() const { return (columns() + 7u) >> 3u; }
+    u32 superblock_rows() const { return blocks_to_superblocks(rows() + 7u); }
+    u32 superblock_columns() const { return blocks_to_superblocks(columns() + 7u); }
 
     Vector2D<FrameBlockContext> const& block_contexts() const { return m_block_contexts; }
 

Userland/Libraries/LibVideo/VP9/Utilities.h

@@ -60,6 +60,18 @@ inline Gfx::Size<u8> block_size_to_sub_blocks(BlockSubsize size)
     return Gfx::Size<u8>(num_4x4_blocks_wide_lookup[size], num_4x4_blocks_high_lookup[size]);
 }
 
+template<Integral T>
+inline T blocks_to_superblocks(T blocks)
+{
+    return blocks >> 3;
+}
+
+template<Integral T>
+inline T superblocks_to_blocks(T superblocks)
+{
+    return superblocks << 3;
+}
+
 template<Integral T>
 inline T blocks_to_sub_blocks(T blocks)
 {