gpu: Add SDR white level to chrome://gpu

Bug: 926173
Change-Id: I04dfcd239ccacd1c68ca7a2b170aa5f22c4d349e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1696349
Auto-Submit: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676222}

content/browser/gpu/gpu_internals_ui.cc

@@ -394,6 +394,9 @@ std::unique_ptr<base::ListValue> getDisplayInfo() {
     display_info->Append(NewDescriptionValuePair("Info ", display.ToString()));
     display_info->Append(NewDescriptionValuePair(
         "Color space information", display.color_space().ToString()));
+    display_info->Append(NewDescriptionValuePair(
+        "SDR white level in nits",
+        base::NumberToString(display.sdr_white_level())));
     display_info->Append(NewDescriptionValuePair(
         "Bits per color component",
         base::NumberToString(display.depth_per_component())));