Revert of gpu: Expose internal format R8 instead of RED.

ui/gl/gl_image_memory.cc

Index: ui/gl/gl_image_memory.cc
diff --git a/ui/gl/gl_image_memory.cc b/ui/gl/gl_image_memory.cc
index cabc6a0972ceabbd5e91b66832903573fccef163..a29a388585fcd41406455446d0156f27deb0075d 100644
--- a/ui/gl/gl_image_memory.cc
+++ b/ui/gl/gl_image_memory.cc
@@ -26,7 +26,7 @@
     case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
     case GL_ETC1_RGB8_OES:
-    case GL_R8:
+    case GL_RED:
     case GL_RGB:
     case GL_RGBA:
     case GL_BGRA_EXT:
@@ -99,9 +99,7 @@
     case BufferFormat::ETC1:
       return GL_ETC1_RGB8_OES;
     case BufferFormat::R_8:
-      return gfx::GLContext::GetCurrent()->GetVersionInfo()->IsES3Capable()
-                 ? GL_R8
-                 : GL_RED;
+      return GL_RED;
     case BufferFormat::RGBA_4444:
     case BufferFormat::RGBA_8888:
       return GL_RGBA;
@@ -127,11 +125,10 @@
       return GL_RGBA;
     case BufferFormat::BGRX_8888:
       return GL_BGRA_EXT;
-    case BufferFormat::R_8:
-      return GL_RED;
-    case BufferFormat::RGBA_4444:
-    case BufferFormat::RGBA_8888:
-    case BufferFormat::BGRA_8888:
+    case BufferFormat::RGBA_4444:
+    case BufferFormat::RGBA_8888:
+    case BufferFormat::BGRA_8888:
+    case BufferFormat::R_8:
     case BufferFormat::ATC:
     case BufferFormat::ATCIA:
     case BufferFormat::DXT1: