void SkColorFilter::onAppendStages(...)

SkColorFilter::onAppendStages() can't actually fail today.
Let's enforce that.  This means the fallback is now used
only for color filters that have not implemented onAppendStages().

Change-Id: Ica3939685694f6186727766b54914b9ba05ca68c
Reviewed-on: https://skia-review.googlesource.com/16231
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/src/effects/SkTableColorFilter.cpp b/src/effects/SkTableColorFilter.cpp
index d9ce98a..b5156ae 100644
--- a/src/effects/SkTableColorFilter.cpp
+++ b/src/effects/SkTableColorFilter.cpp
@@ -103,7 +103,7 @@
         kB_Flag = 1 << 3,
     };
 
-    bool onAppendStages(SkRasterPipeline* p, SkColorSpace*, SkArenaAlloc* alloc,
+    void onAppendStages(SkRasterPipeline* p, SkColorSpace*, SkArenaAlloc* alloc,
                         bool shaderIsOpaque) const override {
         const uint8_t *r = gIdentityTable,
                       *g = gIdentityTable,
@@ -126,7 +126,6 @@
         if (!definitelyOpaque) {
             p->append(SkRasterPipeline::premul);
         }
-        return true;
     }
 
 protected: