Regenerate hover card if Win7 theme changes to/from a non-Aero theme.

See attached bug for rationale.

This approach is simplest, but will reset counters associated with
metrics. However, switch from aero to non-aero in Win7 is extremely
infrequent and shouldn't significantly impact actual numbers.

Bug: 1140256
Change-Id: I479d996e22be1e4f77e55d00080aa3d7a9ca4ddf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2503838Reviewed-by: Caroline Rising <corising@chromium.org>
Commit-Queue: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821462}

chrome/browser/ui/views/tabs/tab_hover_card_bubble_view.cc

@@ -412,7 +412,8 @@ class TabHoverCardBubbleView::ThumbnailObserver
 };
 
 TabHoverCardBubbleView::TabHoverCardBubbleView(Tab* tab)
-    : BubbleDialogDelegateView(tab, views::BubbleBorder::TOP_LEFT) {
+    : BubbleDialogDelegateView(tab, views::BubbleBorder::TOP_LEFT),
+      using_rounded_corners_(CustomShadowsSupported()) {
   SetButtons(ui::DIALOG_BUTTON_NONE);
 
   // We'll do all of our own layout inside the bubble, so no need to inset this
@@ -529,7 +530,7 @@ TabHoverCardBubbleView::TabHoverCardBubbleView(Tab* tab)
       views::BubbleFrameView::PreferredArrowAdjustment::kOffset);
   GetBubbleFrameView()->set_hit_test_transparent(true);
 
-  if (CustomShadowsSupported()) {
+  if (using_rounded_corners_) {
     GetBubbleFrameView()->SetCornerRadius(
         ChromeLayoutProvider::Get()->GetCornerRadiusMetric(
             views::EMPHASIS_HIGH));
@@ -864,6 +865,13 @@ gfx::Size TabHoverCardBubbleView::CalculatePreferredSize() const {
 void TabHoverCardBubbleView::OnThemeChanged() {
   BubbleDialogDelegateView::OnThemeChanged();
 
+  // Bubble closes if the theme changes to the point where the border has to be
+  // regenerated. See crbug.com/1140256
+  if (using_rounded_corners_ != CustomShadowsSupported()) {
+    GetWidget()->Close();
+    return;
+  }
+
   // Update fade labels' background color to match that of the the original
   // label since these child views are ignored by layout.
   title_fade_label_->SetBackgroundColor(title_label_->GetBackgroundColor());

chrome/browser/ui/views/tabs/tab_hover_card_bubble_view.h

@@ -122,6 +122,8 @@ class TabHoverCardBubbleView : public views::BubbleDialogDelegateView {
   size_t hover_cards_seen_count_ = 0;
   bool waiting_for_decompress_ = false;
 
+  const bool using_rounded_corners_;
+
   base::OneShotTimer delayed_show_timer_;
 };