cc: Reformat renderers to make them work with mask tiling.

cc/output/software_renderer.cc

 // Copyright 2012 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/output/software_renderer.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/math_util.h"
 #include "cc/output/copy_output_request.h"
@@ skipping 442 matching lines @@
 
   ResourceProvider::ScopedReadLockSoftware lock(resource_provider_,
                                                 content_texture->id());
   if (!lock.valid())
     return;
 
   SkRect dest_rect = gfx::RectFToSkRect(QuadVertexRect());
   SkRect dest_visible_rect = gfx::RectFToSkRect(
       MathUtil::ScaleRectProportional(QuadVertexRect(), gfx::RectF(quad->rect),
                                       gfx::RectF(quad->visible_rect)));
-  SkRect content_rect = SkRect::MakeWH(quad->rect.width(), quad->rect.height());
+  // TODO(sunxd): make this never be empty.
+  SkRect content_rect =
+      quad->tex_coord_rect.IsEmpty()
+          ? SkRect::MakeWH(quad->rect.width(), quad->rect.height())
+          : RectFToSkRect(quad->tex_coord_rect);
 
   const SkBitmap* content = lock.sk_bitmap();
 
   sk_sp<SkImage> filter_image;
   const FilterOperations* filters = FiltersForPass(quad->render_pass_id);
   if (filters) {
     DCHECK(!filters->IsEmpty());
     sk_sp<SkImageFilter> image_filter = RenderSurfaceFilters::BuildImageFilter(
         *filters, gfx::SizeF(content_texture->size()));
     if (image_filter) {
@@ skipping 236 matching lines @@
       ApplyImageFilter(filter.get(), quad, backdrop_bitmap, nullptr);
 
   if (!filter_backdrop_image)
     return nullptr;
 
   return filter_backdrop_image->makeShader(content_tile_mode, content_tile_mode,
                                            &filter_backdrop_transform);
 }
 
 }  // namespace cc