message: Break out :trmul from :ruy.
  This improves the layering.
diff: @@ -278,14 +278,32 @@ cc_library(
  ],
  )
  +cc_library(
  + name = "trmul",
  + srcs = ["trmul.cc"],
  + hdrs = ["trmul.h"],
  + deps = [
  + ":allocator",
  + ":block_map",
  + ":common",
  + ":context",
  + ":internal_matrix",
  + ":kernel",
  + ":opt_set",
  + ":pack",
  + ":thread_pool",
  + ":trace",
  + ":tune",
  + "@gemmlowp//:profiler",
  + ],
  +)
  +
  # The main library.
  cc_library(
  name = "ruy",
  srcs = [
  "dispatch.h",
  "prepack.h",
  - "trmul.cc",
  - "trmul.h",
  ],
  hdrs = [
  "matrix.h",
  @@ -295,19 +313,12 @@ cc_library(
  ],
  visibility = ruy_visibility(),
  deps = [
  - ":allocator",
  - ":block_map",
  ":check_macros",
  ":common",
  ":context",
  - ":internal_matrix",
  - ":kernel",
  - ":opt_set",
  - ":pack",
  ":size_util",
  ":spec",
  - ":thread_pool",
  - ":trace",
  + ":trmul",
  ":tune",
  "@gemmlowp//:profiler",
  ],
  