gsk: Add a 'colorize' optimization flag

We are going to add an optimization that turns color ops into
colorize ops when beneficial. This flags will make it possible
to turn that off with

GSK_GPU_SKIP=colorize

gsk/gpu/gskgpurenderer.c

@@ -31,7 +31,9 @@ static const GdkDebugKey gsk_gpu_optimization_keys[] = {
   { "gradients", GSK_GPU_OPTIMIZE_GRADIENTS, "Don't supersample gradients" },
   { "mipmap", GSK_GPU_OPTIMIZE_MIPMAP, "Avoid creating mipmaps" },
   { "glyph-align", GSK_GPU_OPTIMIZE_GLYPH_ALIGN, "Never align glyphs to the subpixel grid" },
+  { "colorize", GSK_GPU_OPTIMIZE_COLORIZE, "Don't replace color by colorize" },
 
+  /* These require hardware support */
   { "gl-baseinstance", GSK_GPU_OPTIMIZE_GL_BASE_INSTANCE, "Assume no ARB/EXT_base_instance support" },
 };
 

gsk/gpu/gskgputypesprivate.h

@@ -119,7 +119,9 @@ typedef enum {
   GSK_GPU_OPTIMIZE_GRADIENTS            = 1 <<  4,
   GSK_GPU_OPTIMIZE_MIPMAP               = 1 <<  5,
   GSK_GPU_OPTIMIZE_GLYPH_ALIGN          = 1 <<  6,
+  GSK_GPU_OPTIMIZE_COLORIZE             = 1 <<  7,
+
   /* These require hardware support */
-  GSK_GPU_OPTIMIZE_GL_BASE_INSTANCE     = 1 <<  7,
+  GSK_GPU_OPTIMIZE_GL_BASE_INSTANCE     = 1 <<  16,
 } GskGpuOptimizations;