Allow task pools to reason about transparency.

cc/resources/resource_provider.h

Index: cc/resources/resource_provider.h
diff --git a/cc/resources/resource_provider.h b/cc/resources/resource_provider.h
index 99947e57c68fc793139dc50a3f2605c21d3a5b75..cdac04c10c29908197e75e44f58c912c8b9c17f8 100644
--- a/cc/resources/resource_provider.h
+++ b/cc/resources/resource_provider.h
@@ -94,9 +94,7 @@ class CC_EXPORT ResourceProvider
   void DidLoseOutputSurface() { lost_output_surface_ = true; }
 
   int max_texture_size() const { return max_texture_size_; }
-  ResourceFormat memory_efficient_texture_format() const {
-    return use_rgba_4444_texture_format_ ? RGBA_4444 : best_texture_format_;
-  }
+  ResourceFormat memory_efficient_texture_format(bool must_support_alpha) const;

[reveman, 2015/09/22 14:18:49]

Can we remove this function from ResourceProvider and instead pass the
use_rgba_4444_texture_format_ and future compressed texture settings directly to
the TileTaskWorkerPool impls? That's the only place we use this function so it
doesn't really need to be here. It just adds additional plumbing and makes the
code harder to follow imo.

[christiank, 2015/09/23 12:29:12]

Makes sense, fixed.

   ResourceFormat best_texture_format() const { return best_texture_format_; }
   ResourceFormat best_render_buffer_format() const {
     return best_render_buffer_format_;