add colortable support to imagegenerator

BUG=skia:
R=halcanary@google.com, scroggo@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/304443003

git-svn-id: http://skia.googlecode.com/svn/trunk@14916 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 18 insertions, 6 deletions

diff --git a/src/lazy/SkDiscardablePixelRef.cpp b/src/lazy/SkDiscardablePixelRef.cpp
index ccf812ce6f..b0bbd27e3a 100644
--- a/src/lazy/SkDiscardablePixelRef.cpp
+++ b/src/lazy/SkDiscardablePixelRef.cpp
@@ -60,15 +60,30 @@ bool SkDiscardablePixelRef::onNewLockPixels(LockRec* rec) {
     }
 
     void* pixels = fDiscardableMemory->data();
-    if (!fGenerator->getPixels(this->info(), pixels, fRowBytes)) {
+    const SkImageInfo& info = this->info();
+    SkPMColor colors[256];
+    int colorCount = 0;
+
+    if (!fGenerator->getPixels(info, pixels, fRowBytes, colors, &colorCount)) {
         fDiscardableMemory->unlock();
         SkDELETE(fDiscardableMemory);
         fDiscardableMemory = NULL;
         return false;
     }
 
+    // Note: our ctable is not purgable, as it is not stored in the discardablememory block.
+    // This is because SkColorTable is refcntable, and therefore our caller could hold onto it
+    // beyond the scope of a lock/unlock. If we change the API/lifecycle for SkColorTable, we
+    // could move it into the block, but then again perhaps it is small enough that this doesn't
+    // really matter.
+    if (colorCount > 0) {
+        fCTable.reset(SkNEW_ARGS(SkColorTable, (colors, colorCount)));
+    } else {
+        fCTable.reset(NULL);
+    }
+
     rec->fPixels = pixels;
-    rec->fColorTable = NULL;
+    rec->fColorTable = fCTable.get();
     rec->fRowBytes = fRowBytes;
     return true;
 }
diff --git a/src/lazy/SkDiscardablePixelRef.h b/src/lazy/SkDiscardablePixelRef.h
index e5e1c9f0e1..52a1d6ce37 100644
--- a/src/lazy/SkDiscardablePixelRef.h
+++ b/src/lazy/SkDiscardablePixelRef.h
@@ -17,10 +17,6 @@
  *  A PixelRef backed by SkDiscardableMemory, with the ability to
  *  re-generate the pixels (via a SkImageGenerator) if the DM is
  *  purged.
- *
- *  Since SkColorTable is reference-counted, we do not support indexed
- *  color with this class; there would be no way for the discardable
- *  memory system to unref the color table.
  */
 class SkDiscardablePixelRef : public SkPixelRef {
 public:
@@ -46,6 +42,7 @@ private:
     // PixelRef, since the SkBitmap doesn't expect them to change.
 
     SkDiscardableMemory* fDiscardableMemory;
+    SkAutoTUnref<SkColorTable> fCTable;
 
     /* Takes ownership of SkImageGenerator. */
     SkDiscardablePixelRef(const SkImageInfo&, SkImageGenerator*,