Improve debugging/testing features for layout types.

Adds better output for EXPECT/DCHECK/ASSERT around common layout types
including SizeBounds, as well as providing ToString() methods for
ProposedLayout and ChildLayout used by all LayoutManagerBase-derived
layout managers.

Change-Id: If9c5c99ac3aec2db4969038739fea6118e893191
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1958695
Commit-Queue: Dana Fried <dfried@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Auto-Submit: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723657}

ui/views/BUILD.gn

@@ -915,6 +915,7 @@ jumbo_source_set("test_support") {
     "test/desktop_test_views_delegate.h",
     "test/focus_manager_test.cc",
     "test/focus_manager_test.h",
+    "test/layout_test_utils.cc",
     "test/menu_runner_test_api.cc",
     "test/menu_runner_test_api.h",
     "test/menu_test_utils.cc",

ui/views/layout/layout_types.h

@@ -5,6 +5,7 @@
 #ifndef UI_VIEWS_LAYOUT_LAYOUT_TYPES_H_
 #define UI_VIEWS_LAYOUT_LAYOUT_TYPES_H_
 
+#include <ostream>
 #include <string>
 
 #include "base/optional.h"
@@ -53,6 +54,12 @@ class VIEWS_EXPORT SizeBounds {
   base::Optional<int> height_;
 };
 
+// These are declared here for use in gtest-based unit tests but is defined in
+// the views_test_support target. Depend on that to use this in your unit test.
+// This should not be used in production code - call ToString() instead.
+void PrintTo(const SizeBounds& size_bounds, ::std::ostream* os);
+void PrintTo(LayoutOrientation layout_orientation, ::std::ostream* os);
+
 }  // namespace views
 
 #endif  // UI_VIEWS_LAYOUT_LAYOUT_TYPES_H_

ui/views/layout/proposed_layout.cc

@@ -17,6 +17,13 @@ bool ChildLayout::operator==(const ChildLayout& other) const {
          (!visible || bounds == other.bounds);
 }
 
+std::string ChildLayout::ToString() const {
+  std::ostringstream oss;
+  oss << "{" << child_view << (visible ? " visible " : " not visible ")
+      << bounds.ToString() << "}";
+  return oss.str();
+}
+
 ProposedLayout::ProposedLayout() = default;
 ProposedLayout::ProposedLayout(const ProposedLayout& other) = default;
 ProposedLayout::ProposedLayout(ProposedLayout&& other) = default;
@@ -33,6 +40,21 @@ bool ProposedLayout::operator==(const ProposedLayout& other) const {
   return host_size == other.host_size && child_layouts == other.child_layouts;
 }
 
+std::string ProposedLayout::ToString() const {
+  std::ostringstream oss;
+  oss << "{" << host_size.ToString() << " {";
+  bool first = true;
+  for (const auto& child_layout : child_layouts) {
+    if (first)
+      first = false;
+    else
+      oss << ", ";
+    oss << child_layout.ToString();
+  }
+  oss << "}}";
+  return oss.str();
+}
+
 ProposedLayout ProposedLayoutBetween(double value,
                                      const ProposedLayout& start,
                                      const ProposedLayout& target) {

ui/views/layout/proposed_layout.h

@@ -18,6 +18,8 @@ struct VIEWS_EXPORT ChildLayout {
   bool operator==(const ChildLayout& other) const;
   bool operator!=(const ChildLayout& other) const { return !(*this == other); }
 
+  std::string ToString() const;
+
   View* child_view = nullptr;
   bool visible = false;
   gfx::Rect bounds;
@@ -39,6 +41,8 @@ struct VIEWS_EXPORT ProposedLayout {
     return !(*this == other);
   }
 
+  std::string ToString() const;
+
   // The size of the host view given the size bounds for this layout. If both
   // dimensions of the size bounds are specified, this will be the same size.
   gfx::Size host_size;

ui/views/test/layout_test_utils.cc

+// Copyright 2019 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 <ostream>
+
+#include "ui/views/layout/layout_types.h"
+
+namespace views {
+
+void PrintTo(const SizeBounds& size_bounds, ::std::ostream* os) {
+  *os << size_bounds.ToString();
+}
+
+void PrintTo(LayoutOrientation layout_orientation, ::std::ostream* os) {
+  switch (layout_orientation) {
+    case LayoutOrientation::kHorizontal:
+      *os << "LayoutOrientation::kHorizontal";
+      break;
+    case LayoutOrientation::kVertical:
+      *os << "LayoutOrientation::kVertical";
+      break;
+  }
+}
+
+}  // namespace views