Revert "Remove attach and detach glyph cache."

This reverts commit 61d56b92a4076f8afd644d015913641d691e39c8.

Reason for revert: broke gldft text

Original change's description:
> Remove attach and detach glyph cache.
> 
> BUG=skia:7515
> 
> Change-Id: Ib978e3cf4cfffdefe6453feb520e5e73684abf2e
> Reviewed-on: https://skia-review.googlesource.com/112560
> Reviewed-by: Ben Wagner <bungeman@google.com>
> Commit-Queue: Herb Derby <herb@google.com>

TBR=bungeman@google.com,herb@google.com

Change-Id: Id5723a3abcd103ed20197bba2dab06e8074be633
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:7515
Reviewed-on: https://skia-review.googlesource.com/112745
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Herb Derby <herb@google.com>
diff --git a/samplecode/SamplePathText.cpp b/samplecode/SamplePathText.cpp
index c6c07ee..b6a730f 100644
--- a/samplecode/SamplePathText.cpp
+++ b/samplecode/SamplePathText.cpp
@@ -25,7 +25,7 @@
     PathText() {
         SkPaint defaultPaint;
         SkAutoGlyphCache agc(defaultPaint, nullptr, &SkMatrix::I());
-        SkGlyphCache* cache = agc.get();
+        SkGlyphCache* cache = agc.getCache();
         SkPath glyphPaths[52];
         for (int i = 0; i < 52; ++i) {
             // I and l are rects on OS X ...