Canvas2D setTransform should be invertible tolerant.

Canvas spec indicates in http://www.w3.org/TR/2dcontext2/#dom-context-2d-settransform
The setTransform(a, b, c, d, e, f) method must reset the current transform to
the identity matrix, and then invoke the transform(a, b, c, d, e, f) method with
the same arguments.

Currently, setTransform returns immediately if current transform is
not-invertible.

This CL allows setTransform to change the current transform although the current
transform is not-invertible. The implementation is the exactly same to the
instruction of the spec. setTransform() calls resetTransform() and then
transform().

BUG=290356
TEST=fast/canvas/canvas-setTransform.html

Review URL: https://chromiumcodereview.appspot.com/23461050

git-svn-id: svn://svn.chromium.org/blink/trunk@157706 bbb929c8-8fbe-4397-9dbb-9b2b20218538