base: Erase unused FOR_EACH_OBSERVER macro.

We use the range based for loop from now.

BUG=655021

Review-Url: https://codereview.chromium.org/2451933003
Cr-Commit-Position: refs/heads/master@{#427623}


CrOS-Libchrome-Original-Commit: 802c2138162919a3602f4eb20feb3e4020b81438
3 files changed
tree: 62c149fd1d7a4ce3715a5a52e92a17af6fd86e29
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/