[vr] Handle alignment in linear layout

This CL follows the approach described on crbug.com/808527 for
respecting element alignment in the linear layout.

Bug: 808527
Cq-Include-Trybots: luci.chromium.try:linux_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_vr;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Ia11640da59ebcaf14ddd5d82df182ed7cacfd027
Reviewed-on: https://chromium-review.googlesource.com/964787Reviewed-by: Christopher Grant <cjgrant@chromium.org>
Commit-Queue: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543507}

chrome/browser/vr/elements/linear_layout.cc

@@ -77,10 +77,31 @@ void LinearLayout::LayOutChildren() {
   for (auto& child : children()) {
     if (!child->requires_layout())
       continue;
-    float extent = GetExtent(*child, horizontal);
-    float offset = cumulative_offset + 0.5 * extent;
-    child->SetLayoutOffset(offset * x_factor, offset * y_factor);
-    cumulative_offset += extent + margin_;
+    float child_extent = GetExtent(*child, horizontal);
+    float child_minor_extent = GetExtent(*child, !horizontal);
+    float offset = cumulative_offset + 0.5 * child_extent;
+    float x_align_offset = 0.0f;
+    float y_align_offset = 0.0f;
+    if (Horizontal()) {
+      DCHECK_NE(RIGHT, child->x_anchoring());
+      DCHECK_NE(LEFT, child->x_anchoring());
+      if (child->y_anchoring() == TOP || child->y_anchoring() == BOTTOM) {
+        y_align_offset = 0.5f * (minor_extent - child_minor_extent);
+        if (child->y_anchoring() == BOTTOM)
+          y_align_offset *= -1.0f;
+      }
+    } else {
+      DCHECK_NE(TOP, child->y_anchoring());
+      DCHECK_NE(BOTTOM, child->y_anchoring());
+      if (child->x_anchoring() == RIGHT || child->x_anchoring() == LEFT) {
+        x_align_offset = 0.5f * (minor_extent - child_minor_extent);
+        if (child->x_anchoring() == LEFT)
+          x_align_offset *= -1.0f;
+      }
+    }
+    child->SetLayoutOffset(offset * x_factor + x_align_offset,
+                           offset * y_factor + y_align_offset);
+    cumulative_offset += child_extent + margin_;
   }
 
   SetSize(horizontal ? total_extent : minor_extent,

chrome/browser/vr/elements/linear_layout_unittest.cc

@@ -26,7 +26,7 @@ class TestElement : public UiElement {
 
 }  // namespace
 
-TEST(LinearLayout, HorizontalLayout) {
+TEST(LinearLayout, HorizontalVerticalLayout) {
   LinearLayout layout(LinearLayout::kRight);
   layout.set_margin(10);
   auto element = std::make_unique<UiElement>();
@@ -62,6 +62,72 @@ TEST(LinearLayout, HorizontalLayout) {
 
   rect_a->set_requires_layout(false);
   layout.LayOutChildren();
+
+  EXPECT_FLOAT_EQ(20.0f, layout.size().width());
+}
+
+TEST(LinearLayout, Alignment) {
+  LinearLayout layout(LinearLayout::kRight);
+  layout.set_margin(10);
+  auto element = std::make_unique<UiElement>();
+  UiElement* rect_a = element.get();
+  rect_a->SetSize(1, 1);
+  layout.AddChild(std::move(element));
+  element = std::make_unique<UiElement>();
+  UiElement* rect_b = element.get();
+
+  rect_b->SetSize(10, 10);
+  rect_b->SetScale(2.0f, 2.0f, 0.0f);
+  layout.AddChild(std::move(element));
+
+  gfx::Point3F position_a;
+  rect_a->set_y_anchoring(TOP);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(9.5f, position_a.y());
+  position_a = gfx::Point3F();
+  rect_a->set_y_anchoring(BOTTOM);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(-9.5f, position_a.y());
+
+  layout.set_direction(LinearLayout::kLeft);
+  position_a = gfx::Point3F();
+  rect_a->set_y_anchoring(TOP);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(9.5f, position_a.y());
+  position_a = gfx::Point3F();
+  rect_a->set_y_anchoring(BOTTOM);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(-9.5f, position_a.y());
+
+  layout.set_direction(LinearLayout::kDown);
+  position_a = gfx::Point3F();
+  rect_a->set_x_anchoring(LEFT);
+  rect_a->set_y_anchoring(NONE);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(-9.5f, position_a.x());
+  position_a = gfx::Point3F();
+  rect_a->set_x_anchoring(RIGHT);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(9.5f, position_a.x());
+
+  layout.set_direction(LinearLayout::kUp);
+  position_a = gfx::Point3F();
+  rect_a->set_x_anchoring(LEFT);
+  rect_a->set_y_anchoring(NONE);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(-9.5f, position_a.x());
+  position_a = gfx::Point3F();
+  rect_a->set_x_anchoring(RIGHT);
+  layout.LayOutChildren();
+  rect_a->LocalTransform().TransformPoint(&position_a);
+  EXPECT_FLOAT_EQ(9.5f, position_a.x());
 }
 
 TEST(LinearLayout, Orientations) {

chrome/browser/vr/ui_scene_creator.cc

@@ -1032,6 +1032,7 @@ void UiSceneCreator::CreateContentQuad() {
       VR_BIND_LAMBDA([](ContentElement* e,
                         const EditedText& value) { e->UpdateInput(value); },
                      base::Unretained(main_content.get()))));
+
   shadow->AddChild(std::move(main_content));
   resizer->AddChild(std::move(shadow));
   scene_->AddUiElement(k2dBrowsingContentGroup, std::move(resizer));
@@ -1965,7 +1966,6 @@ void UiSceneCreator::CreateOmnibox() {
   omnibox_text_field->set_hit_testable(false);
   omnibox_text_field->SetHintText(
       l10n_util::GetStringUTF16(IDS_SEARCH_OR_TYPE_WEB_ADDRESS));
-  omnibox_text_field->set_x_anchoring(LEFT);
   omnibox_text_field->SetSize(kOmniboxWidthDMM - 2 * kOmniboxTextMarginDMM -
                                   kOmniboxTextFieldIconButtonSizeDMM -
                                   kOmniboxTextFieldRightMargin,