GrAtlas cleanup: Split out GrPlot and GrAtlas

This breaks up GrAtlas into the head of the list (GrAtlas) and the list elements (GrPlot). It also moves all of the GrPlot management code into GrAtlasMgr. It adds a simple pool allocator for GrPlots and removes use of GrPlotMgr.

R=bsalomon@google.com, robertphillips@google.com

Author: jvanverth@google.com

Review URL: https://codereview.chromium.org/24981004

git-svn-id: http://skia.googlecode.com/svn/trunk/include@11508 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/GrGlyph.h b/gpu/GrGlyph.h
index c730f24..fe4c835 100644
--- a/gpu/GrGlyph.h
+++ b/gpu/GrGlyph.h
@@ -11,7 +11,7 @@
 #include "GrRect.h"
 #include "SkPath.h"
 
-class GrAtlas;
+class GrPlot;
 
 /*  Need this to be quad-state:
     - complete w/ image
@@ -22,14 +22,14 @@
 struct GrGlyph {
     typedef uint32_t PackedID;
 
-    GrAtlas*    fAtlas;
+    GrPlot*     fPlot;
     SkPath*     fPath;
     PackedID    fPackedID;
     GrIRect16   fBounds;
     GrIPoint16  fAtlasLocation;
 
     void init(GrGlyph::PackedID packed, const SkIRect& bounds) {
-        fAtlas = NULL;
+        fPlot = NULL;
         fPath = NULL;
         fPackedID = packed;
         fBounds.set(bounds);