Removed the funky 2-stage initialization of PipelineData.

Removed the funky 2-stage initialization of PipelineData.

Use simple old-skool constructors instead. Note that the long repeated
member initializer lists could be reduced a bit by using C++11's
brace-or-equal initializers, which are actually recommended by the
Google C++ style guide in this case, but the ARM toolchain is still
buggy in this area (see patch sets 1 and 2).  :-/

Review URL: https://codereview.chromium.org/913993004

Cr-Commit-Position: refs/heads/master@{#26654}