Update libpng to 1.6.22

third_party/libpng/BUILD.gn

Index: third_party/libpng/BUILD.gn
diff --git a/third_party/libpng/BUILD.gn b/third_party/libpng/BUILD.gn
index 365c4558000df86c36ba7e1678bcb38fb89c2021..5c61dcac8c198721c9f155a1760ef5bef6abef89 100644
--- a/third_party/libpng/BUILD.gn
+++ b/third_party/libpng/BUILD.gn
@@ -7,15 +7,7 @@ import("//build/config/chromecast_build.gni")
 config("libpng_config") {
   include_dirs = [ "." ]
 
-  defines = [
-    "CHROME_PNG_WRITE_SUPPORT",
-    "PNG_USER_CONFIG",
-  ]
-
-  if (is_android || is_chromecast) {
-    #'toolsets': ['target', 'host'],
-    defines += [ "CHROME_PNG_READ_PACK_SUPPORT" ]  # Required by freetype.
-  }
+  defines = []
 
   if (is_win) {
     if (is_component_build) {
@@ -32,7 +24,12 @@ config("libpng_config") {
 config("clang_warnings") {
   if (is_clang) {
     # Upstream uses self-assignment to avoid warnings.
-    cflags = [ "-Wno-self-assign" ]
+    cflags = [
+      # libpng checks that the width is not greater than PNG_SIZE_MAX.
+      # On platforms where size_t is 64-bits, this comparison will always
+      # be false.
+      "-Wno-tautological-constant-out-of-range-compare",
+    ]
   }
 }
 
@@ -42,29 +39,50 @@ source_set("libpng_sources") {
     "png.h",
     "pngconf.h",
     "pngerror.c",
-    "pnggccrd.c",
     "pngget.c",
+    "pnginfo.h",
+    "pnglibconf.h",
     "pngmem.c",
     "pngpread.c",
+    "pngprefix.h",
+    "pngpriv.h",
     "pngread.c",
     "pngrio.c",
     "pngrtran.c",
     "pngrutil.c",
     "pngset.c",
+    "pngstruct.h",
     "pngtrans.c",
-    "pngusr.h",
-    "pngvcrd.c",
     "pngwio.c",
     "pngwrite.c",
     "pngwtran.c",
     "pngwutil.c",
   ]
 
+  defines = []
+
+  if (current_cpu == "x86" || current_cpu == "x64") {
+    sources += [
+      "contrib/intel/filter_sse2_intrinsics.c",
+      "contrib/intel/intel_init.c",
+    ]
+    defines += [ "PNG_INTEL_SSE_OPT=1" ]
+  } else if (current_cpu == "arm" || current_cpu == "arm64") {
+    sources += [
+      "arm/arm_init.c",
+      "arm/filter_neon_intrinsics.c",
+    ]
+    defines += [
+      "PNG_ARM_NEON_OPT=2",
+      "PNG_ARM_NEON_IMPLEMENTATION=1",
+    ]
+  }
+
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 
   if (is_win && is_component_build) {
-    defines = [ "PNG_BUILD_DLL" ]
+    defines += [ "PNG_BUILD_DLL" ]
   }
 
   public_configs = [ ":libpng_config" ]