Update apps grid horizontal margins calculation

Updates how apps grid horizontal margins are calculated with
kScalableAppList feature enabled.

Adds some tests that verify the apps grid layout in fullscreen state.

Bug: 999273
Change-Id: I63f36f6b946afc7b55b66568a8113bf19ce381b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1776715
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#692214}

ash/app_list/views/apps_container_view.cc

@@ -19,6 +19,7 @@
 #include "ash/app_list/views/search_box_view.h"
 #include "ash/app_list/views/suggestion_chip_container_view.h"
 #include "ash/public/cpp/app_list/app_list_config.h"
+#include "ash/public/cpp/app_list/app_list_features.h"
 #include "ash/public/cpp/app_list/app_list_switches.h"
 #include "base/command_line.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -44,6 +45,11 @@ constexpr int kSuggestionChipFullscreenY = 96;
 
 // The ratio of allowed bounds for apps grid view to its maximum margin.
 constexpr int kAppsGridMarginRatio = 16;
+constexpr int kAppsGridMarginRatioForSmallWidth = 12;
+
+// The width threshold under which kAppsGridMarginRatioForSmallWidth should be
+// used to calculate apps grid horizontal margins.
+constexpr int kAppsGridMarginSmallWidthThreshold = 600;
 
 // The minimum margin of apps grid view.
 constexpr int kAppsGridMinimumMargin = 8;
@@ -62,8 +68,15 @@ constexpr float kSuggestionChipOpacityEndProgress = 1;
 gfx::Size AppsContainerView::GetNonAppsGridSize() {
   gfx::Size size;
 
+  // If ScalableAppList feature is enabled, there is no extra horizontal margin
+  // between grid view and the page switcher.
+  const int min_grid_horizontal_margin =
+      app_list_features::IsScalableAppListEnabled()
+          ? 0
+          : kAppsGridMinimumMargin * 2;
+
   // Enlarge with the apps grid view insets and margin.
-  size.Enlarge(kAppsGridMinimumMargin * 2,
+  size.Enlarge(min_grid_horizontal_margin,
                AppsGridView::kFadeoutZoneHeight * 2);
 
   // Enlarge with suggestion chips.
@@ -269,9 +282,15 @@ void AppsContainerView::Layout() {
       rect.set_y(chip_container_rect.bottom());
       rect.set_height(rect.height() - kSuggestionChipFullscreenY -
                       kSuggestionChipContainerHeight);
+
       const int page_switcher_width =
           page_switcher_->GetPreferredSize().width();
-      rect.Inset(kAppsGridPageSwitcherSpacing + page_switcher_width, 0);
+
+      // With scalable app list feature enabled, the margins are calculated from
+      // the edge of the apps container, instead of container bounds inset by
+      // page switcher area.
+      if (!app_list_features::IsScalableAppListEnabled())
+        rect.Inset(kAppsGridPageSwitcherSpacing + page_switcher_width, 0);
 
       // Layout apps grid.
       gfx::Rect grid_rect = rect;
@@ -287,8 +306,13 @@ void AppsContainerView::Layout() {
       apps_grid_view_->SetLayout(cols, rows);
 
       // Calculate the maximum margin of apps grid.
+      const int horizontal_margin_ratio =
+          (app_list_features::IsScalableAppListEnabled() &&
+           rect.width() < kAppsGridMarginSmallWidthThreshold)
+              ? kAppsGridMarginRatioForSmallWidth
+              : kAppsGridMarginRatio;
       const int max_horizontal_margin =
-          grid_rect.width() / kAppsGridMarginRatio;
+          grid_rect.width() / horizontal_margin_ratio;
       const int max_vertical_margin = grid_rect.height() / kAppsGridMarginRatio;
 
       // Calculate the minimum size of apps grid.
@@ -299,22 +323,35 @@ void AppsContainerView::Layout() {
       // keep maximum margin if apps grid can maintain at least
       // |min_grid_size|; Otherwise, always keep at least
       // |kAppsGridMinimumMargin|.
-      const int horizontal_margin =
-          max_horizontal_margin * 2 <= grid_rect.width() - min_grid_size.width()
-              ? max_horizontal_margin
-              : std::max(kAppsGridMinimumMargin,
-                         (grid_rect.width() - min_grid_size.width()) / 2);
-      const int vertical_margin =
-          max_vertical_margin * 2 <= grid_rect.height() - min_grid_size.height()
+      int horizontal_margin = max_horizontal_margin;
+      if (app_list_features::IsScalableAppListEnabled()) {
+        // For scalable app list margins, ensure the max margin allow space for
+        // the page switcher (note that this is larger than
+        // |kAppsGridMinimumMargin|).
+        horizontal_margin =
+            std::max(max_horizontal_margin,
+                     kAppsGridPageSwitcherSpacing + page_switcher_width);
+      } else if (max_horizontal_margin * 2 >
+                 grid_rect.width() - min_grid_size.width()) {
+        horizontal_margin =
+            std::max(kAppsGridMinimumMargin,
+                     (grid_rect.width() - min_grid_size.width()) / 2);
+      }
+
+      int vertical_margin =
+          (max_vertical_margin * 2 <=
+           grid_rect.height() - min_grid_size.height())
               ? max_vertical_margin
               : std::max(kAppsGridMinimumMargin,
                          (grid_rect.height() - min_grid_size.height()) / 2);
+
       grid_rect.Inset(
           horizontal_margin,
           std::max(apps_grid_view_->GetInsets().top(), vertical_margin));
       grid_rect.ClampToCenteredSize(
           apps_grid_view_->GetMaximumTileGridSize(cols, rows));
       grid_rect.Inset(-apps_grid_view_->GetInsets());
+
       apps_grid_view_->SetBoundsRect(grid_rect);
 
       // Record the distance of y position between suggestion chip container

ash/app_list/views/apps_container_view.h

@@ -102,6 +102,7 @@ class APP_LIST_EXPORT AppsContainerView : public HorizontalPage {
     return folder_background_view_;
   }
   AppListFolderView* app_list_folder_view() { return app_list_folder_view_; }
+  PageSwitcher* page_switcher() { return page_switcher_; }
 
   // Updates suggestion chips from app list model.
   void UpdateSuggestionChips();