DevTools: Don't make ContrastInfo isNull() with missing backgroundColors

This is still a valid state where the background color picker
may be displayed.

Bug: https://g-issues.chromium.org/issues/40140133
Change-Id: Ib267bd03c1ea66057d88c50eb7e7520680b2551d
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6441185
Reviewed-by: Alex Rudenko <[email protected]>
Reviewed-by: Simon Zünd <[email protected]>
Commit-Queue: Alexander Pavlov <[email protected]>

Author: Alexander Pavlov

front_end/ui/legacy/components/color_picker/ContrastInfo.ts

@@ -11,7 +11,7 @@ export class ContrastInfo extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
   private contrastRatioThresholds: {
     [x: string]: number,
   }|null;
-  private readonly contrastRationAPCAThreshold: number|null;
+  private readonly contrastRatioAPCAThresholdInternal: number|null;
   private fgColor: Common.Color.Legacy|null;
   private bgColorInternal: Common.Color.Legacy|null;
   private colorFormatInternal: Common.Color.Format|undefined;
@@ -21,24 +21,27 @@ export class ContrastInfo extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
     this.contrastRatioInternal = null;
     this.contrastRatioAPCAInternal = null;
     this.contrastRatioThresholds = null;
-    this.contrastRationAPCAThreshold = 0;
+    this.contrastRatioAPCAThresholdInternal = 0;
     this.fgColor = null;
     this.bgColorInternal = null;
 
     if (!contrastInfo) {
       return;
     }
 
-    if (!contrastInfo.computedFontSize || !contrastInfo.computedFontWeight || !contrastInfo.backgroundColors ||
-        contrastInfo.backgroundColors.length !== 1) {
+    if (!contrastInfo.computedFontSize || !contrastInfo.computedFontWeight) {
       return;
     }
 
     this.isNullInternal = false;
     this.contrastRatioThresholds =
         Common.ColorUtils.getContrastThreshold(contrastInfo.computedFontSize, contrastInfo.computedFontWeight);
-    this.contrastRationAPCAThreshold =
+    this.contrastRatioAPCAThresholdInternal =
         Common.ColorUtils.getAPCAThreshold(contrastInfo.computedFontSize, contrastInfo.computedFontWeight);
+
+    if (!contrastInfo.backgroundColors || contrastInfo.backgroundColors.length !== 1) {
+      return;
+    }
     const bgColorText = contrastInfo.backgroundColors[0];
     const bgColor = Common.Color.parse(bgColorText)?.asLegacyColor();
     if (bgColor) {
@@ -74,7 +77,7 @@ export class ContrastInfo extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
   }
 
   contrastRatioAPCAThreshold(): number|null {
-    return this.contrastRationAPCAThreshold;
+    return this.contrastRatioAPCAThresholdInternal;
   }
 
   setBgColor(bgColor: Common.Color.Legacy): void {