Add --draw-view-bounds-rects to draw bounds rects for all views.

ui/views/view.h

 // Copyright (c) 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.
 
 #ifndef UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <stddef.h>
 
 #include <algorithm>
@@ skipping 43 matching lines @@
 
 namespace ui {
 struct AXActionData;
 struct AXNodeData;
 class Compositor;
 class InputMethod;
 class Layer;
 class NativeTheme;
 class PaintContext;
 class ThemeProvider;
+class TransformRecorder;
 }
 
 namespace views {
 
 class Background;
 class Border;
 class ContextMenuController;
 class DragController;
 class FocusManager;
 class FocusTraversable;
@@ skipping 1315 matching lines @@
   // system using necessary transformations. Returns whether the rect was
   // successfully converted to the ancestor's coordinate system.
   bool ConvertRectForAncestor(const View* ancestor, gfx::RectF* rect) const;
 
   // Convert a rect in the ancestor's coordinate system to the view's
   // coordinate system using necessary transformations. Returns whether the
   // rect was successfully converted from the ancestor's coordinate system
   // to the view's coordinate system.
   bool ConvertRectFromAncestor(const View* ancestor, gfx::RectF* rect) const;
 
+  // Painting ------------------------------------------------------------------

[sky, 2017/03/22 15:26:05]

There's already a section with this name on line 1278. Move there?

[Peter Kasting, 2017/03/22 21:39:11]

Oh hey!  I looked for that and missed it.  Thanks.

+
+  // Returns true if this view should be painted, i.e. is visible and nonempty.

[sky, 2017/03/22 15:26:05]

Can you make this comment more specific. It doesn't check drawn state, which is
intentional, but given the name it's easy to assume if this returns true the
view will be painted, but that isn't necessarily the case.

[Peter Kasting, 2017/03/22 21:39:11]

Done.

+  bool ShouldPaint() const;
+
+  // Returns the offset that should be used when constructing the paint context
+  // for this view.
+  gfx::Vector2d GetPaintContextOffset() const;
+
+  // Adjusts the transform of |recorder| in advance of painting.
+  void SetupTransformRecorderForPainting(ui::TransformRecorder* recorder) const;
+
+  // Recursively calls the painting method |func| on all non-layered children,
+  // in Z order.
+  void RecursivePaintHelper(void (View::*func)(const ui::PaintContext&),
+                            const ui::PaintContext& context);
+
+  // Invokes Paint() and, if necessary, PaintDebugRects().  Should be called
+  // only on the root of a widget/layer.  PaintDebugRects() is invoked as a
+  // separate pass, instead of being rolled into Paint(), so that siblings will
+  // not obscure debug rects.
+  void PaintRoot(const ui::PaintContext& parent_context);

[sky, 2017/03/22 15:26:05]

Generally a 'root' view refers to RootView. That isn't the case for this
function. We don't really have a good name for a view with a layer, so maybe
PaintFromPaintRoot?

[Peter Kasting, 2017/03/22 21:39:11]

Done.

I had the same concerns as you but couldn't think of a better name.  Yours is
better.

+
+  // Draws a semitransparent rect to indicate the bounds of this view.
+  // Recursively does the same for all children.  Invoked only with
+  // --draw-view-bounds-rects.
+  void PaintDebugRects(const ui::PaintContext& parent_context);
+
   // Accelerated painting ------------------------------------------------------
 
   // Creates the layer and related fields for this view.
   void CreateLayer(ui::LayerType layer_type);
 
   // Recursively calls UpdateParentLayers() on all descendants, stopping at any
   // Views that have layers. Calls UpdateParentLayer() for any Views that have
   // a layer with no parent. If at least one descendant had an unparented layer
   // true is returned.
   bool UpdateParentLayers();
@@ skipping 231 matching lines @@
   // Observers -------------------------------------------------------------
 
   base::ObserverList<ViewObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_