[flags][wasm] Remove the enable-webassembly flag in about:flags

This flag does not need to be in about:flags anymore. We do not expect
an end user to disable WebAssembly anymore.

R=titzer@chromium.org, ellyjones@chromium.org

Bug: chromium:907408
Change-Id: I2653d806194caf88c5e4501f84ae76421f4c2449
Reviewed-on: https://chromium-review.googlesource.com/c/1345972Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610357}

chrome/browser/about_flags.cc

@@ -1499,9 +1499,6 @@ const FeatureEntry kFeatureEntries[] = {
     {"enable-javascript-harmony", flag_descriptions::kJavascriptHarmonyName,
      flag_descriptions::kJavascriptHarmonyDescription, kOsAll,
      SINGLE_VALUE_TYPE(switches::kJavaScriptHarmony)},
-    {"enable-webassembly", flag_descriptions::kEnableWasmName,
-     flag_descriptions::kEnableWasmDescription, kOsAll,
-     FEATURE_VALUE_TYPE(features::kWebAssembly)},
     {"enable-webassembly-baseline", flag_descriptions::kEnableWasmBaselineName,
      flag_descriptions::kEnableWasmBaselineDescription, kOsAll,
      FEATURE_VALUE_TYPE(features::kWebAssemblyBaseline)},