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This mostly just adds the missing dependency identified by the checker.

In some cases I looked at the target and added public_deps that I thought were appropriate given the nature of the target.

This renames the generated mojo action names to be foo__generator instead of foo_generator since it is not clear from the current name that it is an internally-generated target and I kept trying to use it. The double-underscore matches the Android generated targets.

In a few cases I changed ordering (sources come before deps in GN style) but I didn't want to make the changes difficult to diff so didn't do it for most cases.

Reland of https://codereview.chromium.org/581273003/
TBR=darin

Review URL: https://codereview.chromium.org/591763002

Cr-Commit-Position: refs/heads/master@{#295841}