[Multipaste] Tweak HTML image scaling strategy

This CL changes the scaling strategy for the images rendered from
HTML code a little bit: shrink the image if it is higher/wider than the
available space.

Bug: 1146556
Change-Id: Ie690bfc3da293eee7c3371bd8892d21b3532f91a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2536431
Auto-Submit: Andrew Xu <andrewxu@chromium.org>
Commit-Queue: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827086}

ash/clipboard/views/clipboard_history_bitmap_item_view.cc

@@ -287,14 +287,11 @@ class ClipboardHistoryBitmapItemView::BitmapContentsView
           scaling_up_ratio = 1.f;
         else
           scaling_up_ratio = std::fmin(width_ratio, height_ratio);
+        DCHECK_LE(scaling_up_ratio, 1.f);
         break;
       }
       case ui::ClipboardInternalFormat::kHtml: {
-        if (width_ratio >= 1.f || height_ratio >= 1.f)
-          scaling_up_ratio = 1.f;
-        else
-          scaling_up_ratio =
-              std::fmin(std::fmax(width_ratio, height_ratio), 1.f);
+        scaling_up_ratio = std::fmax(width_ratio, height_ratio);
         break;
       }
       default:
@@ -302,7 +299,6 @@ class ClipboardHistoryBitmapItemView::BitmapContentsView
         break;
     }
 
-    DCHECK_LE(scaling_up_ratio, 1.f);
     DCHECK_GT(scaling_up_ratio, 0.f);
 
     image_view_->SetImage(image_view_->original_image(),