Load SVGs into memory before parsing

On my Z840, Windows-Clang-Debug, this cuts the total time to construct
(parse) the 72 SVG sources from 66 seconds to 40 seconds. That's still
awful, but all the time is now spent in expat, so further improvements
will require higher level changes.

Bug: skia:
Change-Id: I0dca67ee18652f6fb8647fe8706716d9a01f7cdf
Reviewed-on: https://skia-review.googlesource.com/155603
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
2 files changed