Everyone gets a namespace {}.

src/opts/SkPMFloat_SSSE3.h

Index: src/opts/SkPMFloat_SSSE3.h
diff --git a/src/opts/SkPMFloat_SSSE3.h b/src/opts/SkPMFloat_SSSE3.h
index 9ff73568fcaf24d87eee06bedb203a95a0dd7b17..67116ec2dd1d52aea84afc16aa5c61d595e900d4 100644
--- a/src/opts/SkPMFloat_SSSE3.h
+++ b/src/opts/SkPMFloat_SSSE3.h
@@ -5,6 +5,8 @@
  * found in the LICENSE file.
  */
 
+namespace {  // See SkPMFloat.h
+
 // For SkPMFloat(SkPMColor), we widen our 8 bit components (fix8) to 8-bit components in 32 bits
 // (fix8_32), then convert those to floats.
 
@@ -81,3 +83,5 @@ inline void SkPMFloat::RoundClampTo4PMColors(
     SkPMColorAssert(colors[2]);
     SkPMColorAssert(colors[3]);
 }
+
+}  // namespace