Bug 947588. Part 1: Add "-moz-control-character-visibility" property to the style system. r=heycam
Ideally we'd make this property inaccessible to Web content style sheets, but
that seems hard since view-source and plain text documents seem to load in a
context that's very similar to Web content as far as the style system is
concerned. It doesn't matter much since it's quite safe and unlikely to be
discovered or used by anyone.

--HG--
extra : rebase_source : 009aafc992afd07fd76a9026afe0f6994b4b214a
Bug 947588. Part 2: Add gfxTextRunFactory::TEXT_HIDE_CONTROL_CHARACTERS to guard usage of IsInvalidControlChar. r=jfkthame

--HG--
extra : rebase_source : 2ce426ebf3ad1643038954bcb18553dec27153c9
Bug 947588. Part 3: Map nsStyleText::mControlCharacterVisibility to TEXT_HIDE_CONTROL_CHARACTERS flag in nsTextFrame. r=jfkthame
Note that this is set up so any use of gfxTextRun outside of nsTextFrame
shows hexboxes for control characters.

--HG--
extra : rebase_source : 83335c85c4db4a6391f18924aad566b00fd6a66c
Bug 947588. Part 3.9: Remove CRs from plaintext.css. r=heycam

--HG--
extra : rebase_source : 0cf0bb02d4edcc848f71ec498fd2521312521ae8
Bug 947588. Part 4: Set -moz-text-discard:none in devtools, XUL, text inputs, plaintext documents, view-source documents. r=heycam

--HG--
extra : rebase_source : 2db920396d9c5f8de51c4385250f2903629441fc
Bug 947588. Part 5: Fix tests to pass even if regular HTML content is not displaying hexboxes for control characters. r=jfkthame

--HG--
extra : rebase_source : 8eea41432c267b4ace85d1230c5dba76fe7cc3c4