Revert "Shrink GrDrawOpAtlases when no longer needed"

This reverts commit 7cf59526c9b1ab3682e875d449200e51f3b6ff32.

Reason for revert: Red red bots... it's tearing me apart...

Original change's description:
> Shrink GrDrawOpAtlases when no longer needed
> 
> Bug: skia:3550
> Change-Id: I7b09aa2b0fd22ed99694f32f9f395392ef80e238
> Reviewed-on: https://skia-review.googlesource.com/49901
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=jvanverth@google.com,bsalomon@google.com,robertphillips@google.com

Change-Id: I8331ec79b0796e1f75d7cc53b9753f886aea7fcd
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:3550
Reviewed-on: https://skia-review.googlesource.com/50220
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>

1 files changed, 9 insertions, 36 deletions

diff --git a/src/gpu/GrDrawOpAtlas.h b/src/gpu/GrDrawOpAtlas.h
index d4a81a0106..87d9c5b619 100644
--- a/src/gpu/GrDrawOpAtlas.h
+++ b/src/gpu/GrDrawOpAtlas.h
@@ -26,29 +26,14 @@ struct GrDrawOpAtlasConfig {
 };
 
 /**
- * This class manages one or more atlas textures on behalf of GrDrawOps. The draw ops that use the
- * atlas perform texture uploads when preparing their draws during flush. The class provides
- * facilities for using GrDrawOpUploadToken to detect data hazards. Op's uploads are performed in
- * "asap" mode until it is impossible to add data without overwriting texels read by draws that
- * have not yet executed on the gpu. At that point, the atlas will attempt to allocate a new
- * atlas texture (or "page") of the same size, up to a maximum number of textures, and upload
- * to that texture. If that's not possible, the uploads are performed "inline" between draws. If a
- * single draw would use enough subimage space to overflow the atlas texture then the atlas will
- * fail to add a subimage. This gives the op the chance to end the draw and begin a new one.
- * Additional uploads will then succeed in inline mode.
- *
- * When the atlas has multiple pages, new uploads are prioritized to the lower index pages, i.e.,
- * it will try to upload to page 0 before page 1 or 2. To keep the atlas from continually using
- * excess space, periodic garbage collection is needed to shift data from the higher index pages to
- * the lower ones, and then eventually remove any pages that are no longer in use. "In use" is
- * determined by using the GrDrawUploadToken system: After a flush each subarea of the page
- * is checked to see whether it was used in that flush; if it is not, a counter is incremented.
- * Once that counter reaches a threshold that subarea is considered to be no longer in use.
- *
- * Garbage collection is initiated by the GrDrawOpAtlas's client via the compact() method. One
- * solution is to make the client a subclass of GrOnFlushCallbackObject, register it with the
- * GrContext via addOnFlushCallbackObject(), and the client's postFlush() method calls compact()
- * and passes in the given GrDrawUploadToken.
+ * This class manages an atlas texture on behalf of GrDrawOps. The draw ops that use the atlas
+ * perform texture uploads when preparing their draws during flush. The class provides facilities
+ * for using GrDrawOpUploadToken to detect data hazards. Op's uploads are performed in "asap" mode
+ * until it is impossible to add data without overwriting texels read by draws that have not yet
+ * executed on the gpu. At that point the uploads are performed "inline" between draws. If a single
+ * draw would use enough subimage space to overflow the atlas texture then the atlas will fail to
+ * add a subimage. This gives the op the chance to end the draw and begin a new one. Additional
+ * uploads will then succeed in inline mode.
  */
 class GrDrawOpAtlas {
 public:
@@ -201,8 +186,6 @@ public:
         }
     }
 
-    void compact(GrDrawOpUploadToken startTokenForNextFlush);
-
     static constexpr auto kGlyphMaxDim = 256;
     static bool GlyphTooLargeForAtlas(int width, int height) {
         return width > kGlyphMaxDim || height > kGlyphMaxDim;
@@ -257,10 +240,6 @@ private:
         void uploadToTexture(GrDrawOp::WritePixelsFn&, GrTextureProxy*);
         void resetRects();
 
-        int flushesSinceLastUsed() { return fFlushesSinceLastUse; }
-        void resetFlushesSinceLastUsed() { fFlushesSinceLastUse = 0; }
-        void incFlushesSinceLastUsed() { fFlushesSinceLastUse++; }
-
     private:
         Plot(int pageIndex, int plotIndex, uint64_t genID, int offX, int offY, int width, int height,
              GrPixelConfig config);
@@ -286,8 +265,6 @@ private:
 
         GrDrawOpUploadToken   fLastUpload;
         GrDrawOpUploadToken   fLastUse;
-        // the number of flushes since this plot has been last used
-        int                   fFlushesSinceLastUse;
 
         struct {
             const uint32_t fPageIndex : 16;
@@ -333,12 +310,10 @@ private:
         fPages[pageIdx].fPlotList.remove(plot);
         fPages[pageIdx].fPlotList.addToHead(plot);
 
-        // No MRU update for pages -- since we will always try to add from
-        // the front and remove from the back there is no need for MRU.
+        // TODO: make page MRU
     }
 
     bool createNewPage();
-    void deleteLastPage();
 
     inline void processEviction(AtlasID);
 
@@ -351,8 +326,6 @@ private:
     SkDEBUGCODE(uint32_t  fNumPlots;)
 
     uint64_t              fAtlasGeneration;
-    // nextTokenToFlush() value at the end of the previous flush
-    GrDrawOpUploadToken   fPrevFlushToken;
 
     struct EvictionData {
         EvictionFunc fFunc;