Add experiment aom_qm_ext and its dependency

Change-Id: I243e2a3cbae5b4eebe7fbabcb9f55552e9f13bd8

build/cmake/aom_config_defaults.cmake

@@ -107,6 +107,7 @@ set(CONFIG_SYMBOLRATE 0 CACHE NUMBER "Enables symbol rate accounting.")
 # AV1 experiment flags.
 set(CONFIG_AMVR 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_AOM_QM 1 CACHE NUMBER "AV1 experiment flag.")
+set(CONFIG_AOM_QM_EXT 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_BGSPRITE 0 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_CFL 1 CACHE NUMBER "AV1 experiment flag.")
 set(CONFIG_CICP 0 CACHE NUMBER "AV1 experiment flag.")

build/cmake/aom_experiment_deps.cmake

@@ -137,6 +137,12 @@ macro (fix_experiment_configs)
       change_config_and_warn(CONFIG_LV_MAP 1 CONFIG_TXK_SEL)
     endif ()
   endif ()
+
+  if (CONFIG_AOM_QM_EXT)
+    if (NOT CONFIG_AOM_QM)
+      change_config_and_warn(CONFIG_AOM_QM 1 CONFIG_AOM_QM_EXT)
+    endif ()
+  endif ()
 endmacro ()
 
 endif ()  # AOM_BUILD_CMAKE_AOM_EXPERIMENT_DEPS_CMAKE_