Fix up and rename VisibleMargins() in preparation for making use of it.

ui/gfx/paint_vector_icon.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 "ui/gfx/paint_vector_icon.h"
 
 #include <map>
 #include <tuple>
 
 #include "base/i18n/rtl.h"
@@ skipping 293 matching lines @@
         id_(VectorIconId::VECTOR_ICON_NONE),
         path_(PathFromSource(definition)),
         color_(color),
         badge_id_(VectorIconId::VECTOR_ICON_NONE) {}
 
   ~VectorIconSource() override {}
 
   // CanvasImageSource:
   void Draw(gfx::Canvas* canvas) override {
     if (path_.empty()) {
-      PaintVectorIcon(canvas, id_, size_.width(), color_);
+      if (id_ != VectorIconId::VECTOR_ICON_NONE)
+        PaintVectorIcon(canvas, id_, size_.width(), color_);
       if (badge_id_ != VectorIconId::VECTOR_ICON_NONE)
         PaintVectorIcon(canvas, badge_id_, size_.width(), color_);
     } else {
       PaintPath(canvas, path_.data(), size_.width(), color_);
     }
   }
 
  private:
   const VectorIconId id_;
   const std::vector<PathElement> path_;
@@ skipping 53 matching lines @@
 
 static base::LazyInstance<VectorIconCache> g_icon_cache =
     LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 void PaintVectorIcon(Canvas* canvas,
                      VectorIconId id,
                      size_t dip_size,
                      SkColor color) {
-  DCHECK(VectorIconId::VECTOR_ICON_NONE != id);
+  DCHECK(id != VectorIconId::VECTOR_ICON_NONE);
   const PathElement* path = canvas->image_scale() == 1.f
                                 ? GetPathForVectorIconAt1xScale(id)
                                 : GetPathForVectorIcon(id);
   PaintPath(canvas, path, dip_size, color);
 }
 
 ImageSkia CreateVectorIcon(VectorIconId id, size_t dip_size, SkColor color) {
   return CreateVectorIconWithBadge(id, dip_size, color,
                                    VectorIconId::VECTOR_ICON_NONE);
 }
 
 ImageSkia CreateVectorIconWithBadge(VectorIconId id,

[Evan Stade, 2016/03/29 03:04:14]

So we're calling this with id == VECTOR_ICON_NONE? It's not clear to me that
isn't some kind of error, not knowing where this is happening from. (It still
wasn't obvious to me after looking at the other CL.) But perhaps if it's decided
this is valid, we should instead insert this early-out:

if (id == VECTOR_ICON_NONE)
  return gfx::ImageSkia();

                                     size_t dip_size,
                                     SkColor color,
                                     VectorIconId badge_id) {
   return g_icon_cache.Get().GetOrCreateIcon(id, dip_size, color, badge_id);
 }
 
 ImageSkia CreateVectorIconFromSource(const std::string& source,
                                      size_t dip_size,
                                      SkColor color) {
   return ImageSkia(
       new VectorIconSource(source, dip_size, color),
       gfx::Size(static_cast<int>(dip_size), static_cast<int>(dip_size)));
 }
 
 }  // namespace gfx