gpu, cmaa: reuse CopyTextureCHROMIUMResourceManager

gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc

Index: gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
index 8b53d0f4c402449b60fab2c23a0e1b514bb7307d..e6e3035c9e868ccbd11a5107ad5e919d9d4fca64 100644
--- a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
+++ b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
@@ -473,6 +473,14 @@ void CopyTextureCHROMIUMResourceManager::DoCopySubTexture(
     bool flip_y,
     bool premultiply_alpha,
     bool unpremultiply_alpha) {
+  bool use_gl_copy_tex_sub_image_2d = true;
+#if defined(OS_CHROMEOS) && defined(ARCH_CPU_X86_FAMILY)
+  // glDrawArrays is faster than glCopyTexSubImage2D on IA Mesa driver,
+  // although opposite in Android.
+  // TODO(dshwang): After Mesa fixes this issue, remove this hack.
+  // https://bugs.freedesktop.org/show_bug.cgi?id=98478 crbug.com/535198
+  use_gl_copy_tex_sub_image_2d = false;
+#endif
   bool premultiply_alpha_change = premultiply_alpha ^ unpremultiply_alpha;
   // GL_INVALID_OPERATION is generated if the currently bound framebuffer's
   // format does not contain a superset of the components required by the base
@@ -484,8 +492,8 @@ void CopyTextureCHROMIUMResourceManager::DoCopySubTexture(
       (source_internal_format == GL_RGBA && dest_internal_format == GL_RGB);
   // GL_TEXTURE_RECTANGLE_ARB on FBO is supported by OpenGL, not GLES2,
   // so restrict this to GL_TEXTURE_2D.
-  if (source_target == GL_TEXTURE_2D && dest_target == GL_TEXTURE_2D &&
-      !flip_y && !premultiply_alpha_change &&
+  if (use_gl_copy_tex_sub_image_2d && source_target == GL_TEXTURE_2D &&
+      dest_target == GL_TEXTURE_2D && !flip_y && !premultiply_alpha_change &&
       source_format_contain_superset_of_dest_format) {
     DoCopyTexSubImage2D(decoder, source_target, source_id, dest_target, dest_id,
                         xoffset, yoffset, x, y, width, height, framebuffer_);