[WIP] cc: Use sRGB for rastering non-wide-color-gamut content

cc/paint/discardable_image_map.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/paint/discardable_image_map.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 12 matching lines @@
   DCHECK(all_images_.empty());
   return base::MakeUnique<DiscardableImageStore>(
       bounds.width(), bounds.height(), &all_images_, &image_id_to_rect_);
 }
 
 void DiscardableImageMap::EndGeneratingMetadata() {
   images_rtree_.Build(all_images_,
                       [](const std::pair<DrawImage, gfx::Rect>& image) {
                         return image.second;
                       });
+  for (const auto& image_rect_pair : all_images_) {

[vmpstr, 2017/05/09 22:58:27]

You can just pass &has_non_srgb_images_ to DiscardableImageStore ctor (like we
do with all_images_) and set it whenever we find an image. That saves an extra
pass through the images.  

+    const DrawImage& draw_image = image_rect_pair.first;
+    SkColorSpace* color_space = draw_image.image()->colorSpace();
+    if (color_space && !color_space->isSRGB()) {
+      has_non_srgb_images_ = true;
+      break;
+    }
+  }
 }
 
 void DiscardableImageMap::GetDiscardableImagesInRect(
     const gfx::Rect& rect,
     float contents_scale,
     const gfx::ColorSpace& target_color_space,
     std::vector<DrawImage>* images) const {
   std::vector<size_t> indices;
   images_rtree_.Search(rect, &indices);
   for (size_t index : indices) {
@@ skipping 12 matching lines @@
     DiscardableImageMap* image_map,
     const gfx::Size& bounds)
     : image_map_(image_map),
       image_store_(image_map->BeginGeneratingMetadata(bounds)) {}
 
 DiscardableImageMap::ScopedMetadataGenerator::~ScopedMetadataGenerator() {
   image_map_->EndGeneratingMetadata();
 }
 
 }  // namespace cc