Once Chromium starts holding on to paths and we can actually reuse cached path data...

Once Chromium starts holding on to paths and we can actually reuse cached path data (e.g., masks & geometry) we will need a way to preserve that reuse in the skps. This CL begins adding that capability. More analysis & profiling needs to be done before it is always enabled.

When enabled it does make the disabled path de-duping test in the Canvas unit test pass.

BUG=skia:507
R=bsalomon@google.com, mtklein@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/190923002

git-svn-id: http://skia.googlecode.com/svn/trunk@13709 2bbb7eff-a529-9590-31e7-b0007b416f81