Fix a bug in ShouldForceDirectCompositionRootSurfaceFullDamage().

Forgot to actually call an anonymous function. Surprised compiler
didn't complain.

BUG=1117185
R=sunnyps@chromium.org
TEST=manual

Change-Id: I17a7501c319253dd01a82fc587e03c18e3dc2997
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2367793Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800346}

ui/gl/gl_utils.cc

@@ -130,7 +130,7 @@ bool ShouldForceDirectCompositionRootSurfaceFullDamage() {
     if ((brga_flags & kSupportBits) == 0)
       return false;
     return true;
-  };
+  }();
   return should_force;
 }
 #endif  // OS_WIN