Initialize bool_value_ and double_value_ to default values in policy_value

Bug: 1005779
Change-Id: I915eac43a06592cf2e196632408b4736b4f75f30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1827823Reviewed-by: Ian Clelland <iclelland@chromium.org>
Commit-Queue: Charlie Hu <chenleihu@google.com>
Cr-Commit-Position: refs/heads/master@{#700399}

third_party/blink/public/common/feature_policy/policy_value.h

@@ -59,8 +59,8 @@ class BLINK_COMMON_EXPORT PolicyValue {
 
  private:
   mojom::PolicyValueType type_;
-  bool bool_value_;
-  double double_value_;
+  bool bool_value_ = false;
+  double double_value_ = 0.0;
 };
 
 bool BLINK_COMMON_EXPORT operator==(const PolicyValue& lhs,