Add support for converting cc::FilterOperations into an SkImageFilter

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index a80feac4ecc9f97f3fd5e731d99a43cc7ea98a99..ff35cfca0acfd39863e354310e94d8bbe0ad5265 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -758,16 +758,20 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
   SkBitmap filter_bitmap;
   SkScalar color_matrix[20];
   bool use_color_matrix = false;
-  if (quad->filter) {
+  // TODO(ajuma): Always use RenderSurfaceFilters::BuildImageFilter, not just
+  // when we have a reference filter.

[ajuma, 2013/09/09 17:35:36]

I'm leaving this for a separate CL in order to avoid introducing behavior
changes (the ApplyImageFilter path can produce slightly different results than
the ApplyFilters path) in this already-large CL.

+  if (quad->filters.HasReferenceFilter()) {
+    skia::RefPtr<SkImageFilter> filter = RenderSurfaceFilters::BuildImageFilter(
+        quad->filters, contents_texture->size());
     skia::RefPtr<SkColorFilter> cf;
 
     {
       SkColorFilter* colorfilter_rawptr = NULL;
-      quad->filter->asColorFilter(&colorfilter_rawptr);
+      filter->asColorFilter(&colorfilter_rawptr);
       cf = skia::AdoptRef(colorfilter_rawptr);
     }
 
-    if (cf && cf->asColorMatrix(color_matrix) && !quad->filter->getInput(0)) {
+    if (cf && cf->asColorMatrix(color_matrix) && !filter->getInput(0)) {
       // We have a single color matrix as a filter; apply it locally
       // in the compositor.
       use_color_matrix = true;
@@ -775,7 +779,7 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
       filter_bitmap = ApplyImageFilter(this,
                                        frame->offscreen_context_provider,
                                        quad->rect.origin(),
-                                       quad->filter.get(),
+                                       filter.get(),
                                        contents_texture);
     }
   } else if (!quad->filters.IsEmpty()) {