WebUI Dark Mode: update people page icon colors to match sync account control

R=dpapad@chromium.org
BUG=926658

Change-Id: I9b64c2a2250f73f2e5ab2d8906c259ceb714503d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1506884
Commit-Queue: Dan Beam (slow; perfing) <dbeam@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Auto-Submit: Dan Beam (slow; perfing) <dbeam@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638749}

chrome/browser/resources/settings/people_page/people_page.html

@@ -56,16 +56,25 @@
       }
 
       iron-icon[icon='cr:sync'] {
-       --iron-icon-fill-color: var(--google-green-700);
+        --iron-icon-fill-color: var(--google-green-refresh-700);
+      }
+
+      :host-context([dark]) iron-icon[icon='cr:sync'] {
+        --iron-icon-fill-color: var(--google-green-refresh-300);
       }
 
       #sync-status[actionable] iron-icon[icon='settings:sync-problem'] {
-       --iron-icon-fill-color: var(--settings-error-color);
+        --iron-icon-fill-color: var(--settings-error-color);
       }
 
       #sync-status[actionable].auth-error
           iron-icon[icon='settings:sync-disabled'] {
-       --iron-icon-fill-color: var(--google-blue-500);
+        --iron-icon-fill-color: var(--google-blue-500);
+      }
+
+      :host-context([dark]) #sync-status[actionable].auth-error
+          iron-icon[icon='settings:sync-disabled'] {
+        --iron-icon-fill-color: var(--google-blue-refresh-300);
       }
 
       #sync-status:not([actionable]) .subpage-arrow {