[Code health] A bit coding style change in invalidatable_interpolation.cc

Our coding style is that when there are multi-line statement in an if
or if/else branch, then there should be curly brackets. This CL does
that clean up in invalidatable_interpolation.cc.

TBR=flackr@chromium.org

Bug: None
Change-Id: If7ce2353fafac796afb6ab75fe0ad22868b25007
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1711632
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#679586}

third_party/blink/renderer/core/animation/invalidatable_interpolation.cc

@@ -271,19 +271,21 @@ void InvalidatableInterpolation::ApplyStack(
     current_interpolation.SetFlagIfInheritUsed(environment);
     double underlying_fraction = current_interpolation.UnderlyingFraction();
     if (underlying_fraction == 0 || !underlying_value_owner ||
-        underlying_value_owner.GetType() != current_value->GetType())
+        underlying_value_owner.GetType() != current_value->GetType()) {
       underlying_value_owner.Set(current_value);
-    else
+    } else {
       current_value->GetType().Composite(
           underlying_value_owner, underlying_fraction, current_value->Value(),
           current_interpolation.current_fraction_);
+    }
   }
 
-  if (should_apply && underlying_value_owner)
+  if (should_apply && underlying_value_owner) {
     underlying_value_owner.GetType().Apply(
         *underlying_value_owner.Value().interpolable_value,
         underlying_value_owner.Value().non_interpolable_value.get(),
         environment);
+  }
 }
 
 }  // namespace blink