Don't set the STATE_SYSTEM_HOTTRACKED state in tests.

It's set whenever the mouse is over an element, which just leads
to flakiness.

BUG=454600
NOPRESUBMIT=true

Review URL: https://codereview.chromium.org/896653002

Cr-Commit-Position: refs/heads/master@{#314382}
diff --git a/content/browser/accessibility/browser_accessibility_state_impl.cc b/content/browser/accessibility/browser_accessibility_state_impl.cc
index 597b13a..5d68c2c 100644
--- a/content/browser/accessibility/browser_accessibility_state_impl.cc
+++ b/content/browser/accessibility/browser_accessibility_state_impl.cc
@@ -31,7 +31,8 @@
 
 BrowserAccessibilityStateImpl::BrowserAccessibilityStateImpl()
     : BrowserAccessibilityState(),
-      accessibility_mode_(AccessibilityModeOff) {
+      accessibility_mode_(AccessibilityModeOff),
+      disable_hot_tracking_(false) {
   ResetAccessibilityModeValue();
 #if defined(OS_WIN)
   // On Windows, UpdateHistograms calls some system functions with unknown