Add build flag to disable hotwording.

Hotwording downloads a shared module from the web store containing a NaCl module. There is a desire to build and distribute Chromium without this happening. This change adds an "enable_hotwording" build flag that is enabled by default, but can be disabled at compile time.


Review URL:

Cr-Commit-Position: refs/heads/master@{#333548}
(cherry picked from commit f269d3b548203e217e8c0080c2e22e7ae3efb51e)

Resolved merge conflict: Remove the body of
IsHotwordAllowedDisabledFieldTrial and IsHotwordAllowedInvalidFieldTrial
when ENABLE_HOTWORDING is false. These tests were deleted before the
upstream patch landed.

(Merge approval on,

Review URL:

Cr-Commit-Position: refs/branch-heads/2403@{#412}
Cr-Branched-From: f54b8097a9c45ed4ad308133d49f05325d6c5070-refs/heads/master@{#330231}
5 files changed