Fix the system tray bubble placement.

The system tray bubble's shadow should not overlap the shelf.
This regressed in https://chromium-review.googlesource.com/c/1386432

Add a flag to apply shadow insets before calculating coordinates.
This should restore the previous behavior for tray bubbles.

Bug: 919645
Test: Tray/volume/etc. bubbles placed correctly for all shelf positions.
Change-Id: I3592e73fc67b32dead470e25e14e450fadc08aba
Reviewed-on: https://chromium-review.googlesource.com/c/1457434
Commit-Queue: Manu Cornet <manucornet@chromium.org>
Reviewed-by: Manu Cornet <manucornet@chromium.org>
Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629917}

ash/system/tray/tray_bubble_view.cc

@@ -217,6 +217,7 @@ TrayBubbleView::TrayBubbleView(const InitParams& init_params)
   bubble_border_->set_use_theme_background_color(!init_params.bg_color);
   if (init_params.corner_radius)
     bubble_border_->SetCornerRadius(init_params.corner_radius.value());
+  bubble_border_->set_avoid_shadow_overlap(true);
   set_parent_window(params_.parent_window);
   SetCanActivate(false);
   set_notify_enter_exit_on_child(true);

ui/views/bubble/bubble_border.cc

@@ -91,19 +91,23 @@ gfx::Rect BubbleBorder::GetBounds(const gfx::Rect& anchor_rect,
   // In MD, there are no arrows, so positioning logic is significantly simpler.
   if (has_arrow(arrow_)) {
     gfx::Rect contents_bounds(contents_size);
-    // Apply the border part of the inset before calculating coordinates because
-    // the border should align with the anchor's border. For the purposes of
-    // positioning, the border is rounded up to a dip, which may mean we have
-    // misalignment in scale factors greater than 1. Borders with custom shadow
-    // elevations do not draw the 1px border.
+    // Always apply the border part of the inset before calculating coordinates,
+    // that ensures the bubble's border is aligned with the anchor's border.
+    // For the purposes of positioning, the border is rounded up to a dip, which
+    // may cause misalignment in scale factors greater than 1.
     // TODO(estade): when it becomes possible to provide px bounds instead of
     // dip bounds, fix this.
+    // Borders with custom shadow elevations do not draw the 1px border.
     const gfx::Insets border_insets =
         shadow_ == NO_ASSETS || md_shadow_elevation_.has_value()
             ? gfx::Insets()
             : gfx::Insets(kBorderThicknessDip);
     const gfx::Insets shadow_insets = GetInsets() - border_insets;
     contents_bounds.Inset(-border_insets);
+    // If |avoid_shadow_overlap_| is true, the shadow part of the inset is also
+    // applied now, to ensure that the shadow itself doesn't overlap the anchor.
+    if (avoid_shadow_overlap_)
+      contents_bounds.Inset(-shadow_insets);
     switch (arrow_) {
       case TOP_LEFT:
         contents_bounds += anchor_rect.bottom_left() - contents_bounds.origin();
@@ -156,7 +160,8 @@ gfx::Rect BubbleBorder::GetBounds(const gfx::Rect& anchor_rect,
     // used to position the bubble origin according to |anchor_rect|.
     DCHECK((shadow_ != NO_ASSETS && shadow_ != NO_SHADOW) ||
            shadow_insets.IsEmpty());
-    contents_bounds.Inset(-shadow_insets);
+    if (!avoid_shadow_overlap_)
+      contents_bounds.Inset(-shadow_insets);
     // |arrow_offset_| is used to adjust bubbles that would normally be
     // partially offscreen.
     if (is_arrow_on_horizontal(arrow_))

ui/views/bubble/bubble_border.h

@@ -182,6 +182,9 @@ class VIEWS_EXPORT BubbleBorder : public Border {
     md_shadow_color_ = shadow_color;
   }
 
+  // Set a flag to avoid the bubble's shadow overlapping the anchor.
+  void set_avoid_shadow_overlap(bool value) { avoid_shadow_overlap_ = value; }
+
   // Get the desired widget bounds (in screen coordinates) given the anchor rect
   // and bubble content size; calculated from shadow and arrow image dimensions.
   virtual gfx::Rect GetBounds(const gfx::Rect& anchor_rect,
@@ -245,6 +248,7 @@ class VIEWS_EXPORT BubbleBorder : public Border {
   SkColor md_shadow_color_ = SK_ColorBLACK;
   SkColor background_color_;
   bool use_theme_background_color_;
+  bool avoid_shadow_overlap_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(BubbleBorder);
 };