cc: Implement and use FilterOperations::MapRectReverse for mapping backdrop bounding box.

cc/output/gl_renderer.cc

 // Copyright 2010 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/gl_renderer.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 778 matching lines @@
     bool use_aa) {
   gfx::QuadF scaled_region;
   if (!GetScaledRegion(quad->rect, clip_region, &scaled_region)) {
     scaled_region = SharedGeometryQuad().BoundingBox();
   }
 
   gfx::Rect backdrop_rect = gfx::ToEnclosingRect(MathUtil::MapClippedRect(
       contents_device_transform, scaled_region.BoundingBox()));
 
   if (ShouldApplyBackgroundFilters(quad)) {
-    int top, right, bottom, left;
-    quad->background_filters.GetOutsets(&top, &right, &bottom, &left);
-    backdrop_rect.Inset(-left, -top, -right, -bottom);
+    backdrop_rect =
+        quad->background_filters.MapRectReverse(backdrop_rect, SkMatrix::I());

[Stephen White, 2016/06/01 17:42:46]

If these are device-space rects, shouldn't we be using filters_scale here?

[jbroman, 2016/06/01 19:41:20]

I believe you're correct, which would make that an existing bug, as the
GetOutsets code didn't account for it either. Would you like that addressed in
this CL, or would a followup be good? (Or would you like such a fix to land
first?)

   }
 
   if (!backdrop_rect.IsEmpty() && use_aa) {
     const int kOutsetForAntialiasing = 1;
     backdrop_rect.Inset(-kOutsetForAntialiasing, -kOutsetForAntialiasing);
   }
 
   if (!quad->filters.IsEmpty()) {
     // If we have filters, grab an extra one-pixel border around the
     // background, so texture edge clamping gives us a transparent border
@@ skipping 2805 matching lines @@
       texture_id = pending_overlay_resources_.back()->texture_id();
     }
 
     context_support_->ScheduleOverlayPlane(
         overlay.plane_z_order, overlay.transform, texture_id,
         ToNearestRect(overlay.display_rect), overlay.uv_rect);
   }
 }
 
 }  // namespace cc