Fix broken transition for text-decoration-color.

CSSPropertyEquality::propertiesEqual was not implemented for
text-decoration-color.

Note: The test has a high tolerance, because we really only need to test
that the current value is somewhere between the start value and end value.

BUG=351675
TEST=test-decoration-color-transition.html

Review URL: https://codereview.chromium.org/197223002

git-svn-id: svn://svn.chromium.org/blink/trunk@169215 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make private field names start with underscore in HeapSnapshotView

BUG=None
R=alph@chromium.org

Review URL: https://codereview.chromium.org/195763012

git-svn-id: svn://svn.chromium.org/blink/trunk@169216 bbb929c8-8fbe-4397-9dbb-9b2b20218538
WTF::Vector::swap() should not mem{cpy,move} unsupported classes.

Prior to this CL, swap was always done by memcpy when the vector size was within its inlineCapacity.
However, this caused problems when the class was not memcpy-able.

This CL adds VectorTraits<T>::canSwapWithMemcpy, and VectorSwapper template.
Only classes which are marked canSwapWithMemcpy are swapped with memcpy, and all other classes are swapped via copy c-tor and operator=.

BUG=267349
R=ager@chromium.org, erik.corry@gmail.com, jochen@chromium.org

Review URL: https://codereview.chromium.org/194363002

git-svn-id: svn://svn.chromium.org/blink/trunk@169217 bbb929c8-8fbe-4397-9dbb-9b2b20218538