Bug 834525: New tab thumbnail styling for tabs-ui. [r=mfinkle]

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extra : rebase_source : a774fdea385a9f3e9997adebf730cdb40e9e8a92
Bug 834525: Supress testNewTab's closeTabs(). [r=mfinkle]

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extra : rebase_source : 3bdac1f069856357c9930ac8f075c715b534a812
Bug 834525: Tab is not selected if its private. [r=mfinkle]

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extra : rebase_source : 1889436b29e1e0e96ccd3e353c9419f8c62f22d2
Bug 836043: Use icon-tabs for tab switcher in tabs-ui. [r=mfinkle]

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extra : rebase_source : efa4b1633f7bbf4bcacc4b2140c759f1666386f6
Bug 836043: Replace tabs toolbar background with a dark one. [r=mfinkle]

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extra : rebase_source : cfe5ff7847783a0a58142de1b30abfe53c95d8e8
Bug 836043: Tab icons for tablets are same for 7" and 10". [r=mfinkle]

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extra : rebase_source : b324ce88c3bf057290637dd81d8215094fcc7ae5
Bug 794940: Visible white line in Nexus 7. [r=mfinkle] [needs-clobber]

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extra : rebase_source : 09b4301502fe5aaf75056d163deb325dabcb79f4