gpu: support GL_TEXTURE_CUBE_MAP destination target to Copy(Sub)TextureCHROMIUM.

gpu/command_buffer/common/gles2_cmd_utils.cc

Index: gpu/command_buffer/common/gles2_cmd_utils.cc
diff --git a/gpu/command_buffer/common/gles2_cmd_utils.cc b/gpu/command_buffer/common/gles2_cmd_utils.cc
index e0ca1ecc650ab81fa3746dde630b9dbb7297c856..69c498042a1f439e882646292e11593434833ffb 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils.cc
+++ b/gpu/command_buffer/common/gles2_cmd_utils.cc
@@ -808,6 +808,27 @@ size_t GLES2Util::GLTargetToFaceIndex(uint32 target) {
   }
 }
 
+uint32_t GLES2Util::GLFaceToTarget(uint32_t face) {
+  switch (face) {
+    case GL_TEXTURE_2D:
+    case GL_TEXTURE_EXTERNAL_OES:
+    case GL_TEXTURE_RECTANGLE_ARB:
+    case GL_TEXTURE_3D:
+    case GL_TEXTURE_2D_ARRAY:
+      return face;
+    case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
+    case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
+    case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
+    case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
+    case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
+    case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
+      return GL_TEXTURE_CUBE_MAP;
+    default:
+      NOTREACHED();
+      return GL_TEXTURE_2D;
+  }
+}
+
 uint32 GLES2Util::GetPreferredGLReadPixelsFormat(uint32 internal_format) {
   switch (internal_format) {
     case GL_RGB16F_EXT: