Simplify ComputedStyleBase::inheritedEqual.

Currently ComputedStyleBase::inheritedEqual just does a pairwise compare
over all inherited properties. A more concise implementation is to use
the existing independentInheritedEqual and nonIndependentInheritedEqual
methods. This is what ComputedStyle does. We can switch to a more
efficient when we can think of one.

BUG=628043

Review-Url: https://codereview.chromium.org/2741103003
Cr-Commit-Position: refs/heads/master@{#456995}
1 file changed