Reland: Add ETC1 powered SSE encoder for tile texture compression

cc/resources/texture_compressor.cc

Index: cc/resources/texture_compressor.cc
diff --git a/cc/resources/texture_compressor.cc b/cc/resources/texture_compressor.cc
index 186a47d04b65a7d9539b033a61b5c8d35c1d01f9..7a658b1556e0c8cf27679968aa43c146951dd647 100644
--- a/cc/resources/texture_compressor.cc
+++ b/cc/resources/texture_compressor.cc
@@ -7,12 +7,24 @@
 #include "base/logging.h"
 #include "cc/resources/texture_compressor_etc1.h"
 
+#ifdef __SSE2__

[reveman, 2015/05/07 16:26:29]

#if defined(ARCH_CPU_X86_FAMILY), see comment below

[radu.velea, 2015/05/08 10:52:10]

Done.

+#include "base/cpu.h"
+#include "cc/resources/texture_compressor_etc1_sse.h"
+#endif
+
 namespace cc {
 
 scoped_ptr<TextureCompressor> TextureCompressor::Create(Format format) {
   switch (format) {
-    case kFormatETC1:
+    case kFormatETC1: {
+#ifdef __SSE2__

[reveman, 2015/05/07 16:26:29]

I found another example in the chromium code base where we use sse2.
media/base/yuv_convert.cc

"#if defined(ARCH_CPU_X86_FAMILY)" is used there so I assume that's sufficient
to build this code. I recommend switching to that for consistency.

[radu.velea, 2015/05/08 10:52:11]

Done.

+      base::CPU cpu;
+      if (cpu.has_sse2()) {
+        return make_scoped_ptr(new TextureCompressorETC1SSE());
+      }
+#endif
       return make_scoped_ptr(new TextureCompressorETC1());
+    }
   }
 
   NOTREACHED();