Reland: Add ETC1 powered SSE encoder for tile texture compression

cc/BUILD.gn

Index: cc/BUILD.gn
diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index b35560ade8cbb4edf7332a07377421a369b98bdf..2c72e418e01aabe235a72e0231e6510861d433ec 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn
@@ -550,6 +550,14 @@ component("cc") {
     configs -= [ "//build/config/compiler:optimize" ]
     configs += [ "//build/config/compiler:optimize_max" ]
   }
+
+  if (target_cpu == "ia32" || target_cpu == "x64") {
+    sources += [
+      "resources/texture_compressor_etc1_sse.cc",
+      "resources/texture_compressor_etc1_sse.h",
+    ]
+    cflags = [ "-msse2" ]
+  }
 }
 
 source_set("test_support") {
@@ -807,6 +815,7 @@ test("cc_unittests") {
     "resources/scoped_gpu_raster_unittest.cc",
     "resources/scoped_resource_unittest.cc",
     "resources/task_graph_runner_unittest.cc",
+    "resources/texture_compressor_etc1_unittest.cc",
     "resources/texture_mailbox_deleter_unittest.cc",
     "resources/texture_uploader_unittest.cc",
     "resources/tile_manager_unittest.cc",