clean up SK_LEGACY_HIGH_QUALITY_SCALING_CLAMP

After this rolls out, we can remove
-DSK_LEGACY_HIGH_QUALITY_SCALING_CLAMP from Google and Chromium,
finally.

Change-Id: Ie277843d5ab6e6e762b1b2eea1c23a40cca55a38
Reviewed-on: https://skia-review.googlesource.com/106622
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

BUILD.gn

@@ -144,9 +144,6 @@ config("skia_public") {
   if (skia_enable_atlas_text) {
     defines += [ "SK_SUPPORT_ATLAS_TEXT=1" ]
   }
-
-  # Temporary.
-  defines += [ "SK_LEGACY_HIGH_QUALITY_SCALING_CLAMP" ]
 }
 
 # Skia internal APIs, used by Skia itself and a few test tools.

src/shaders/SkImageShader.cpp

@@ -399,14 +399,12 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
             info.alphaType() == kUnpremul_SkAlphaType) {
             p->append(SkRasterPipeline::premul);
         }
-    #if defined(SK_LEGACY_HIGH_QUALITY_SCALING_CLAMP)
         if (quality > kLow_SkFilterQuality) {
             // Bicubic filtering naturally produces out of range values on both sides.
             p->append(SkRasterPipeline::clamp_0);
             p->append(fClampAsIfUnpremul ? SkRasterPipeline::clamp_1
                                          : SkRasterPipeline::clamp_a);
         }
-    #endif
         append_gamut_transform(p, alloc, info.colorSpace(), rec.fDstCS,
                                fClampAsIfUnpremul ? kUnpremul_SkAlphaType : kPremul_SkAlphaType);
         return true;