Ganesh text rendering cleanup.

Rename GrTextStrike.{cpp.h} to GrFontCache.{cpp,h}
Move contents of GrTextStrike_impl.h to GrFontCache.h
Move glyph uploading to a separate function and remove harmful gotos
Add assert on glyph upload failure (shouldn't happen)

Review URL: https://codereview.chromium.org/780923002
11 files changed