Remove flag: SNAP_OBJECT_USE_CACHE from snap_context

Since the cache is created in one way or another, this flag is not really making a difference
More details here: D2496

source/blender/editors/armature/editarmature_sketch.c

@@ -970,6 +970,9 @@ static int sk_getStrokeSnapPoint(bContext *C, SK_Point *pt, SK_Sketch *sketch, S
 	ToolSettings *ts = CTX_data_tool_settings(C);
 	int point_added = 0;
 
+	/* TODO: Since the function `ED_transform_snap_object_context_create_view3d` creates a cache,
+	 * the ideal would be to call this function only at the beginning of the snap operation,
+	 * or at the beginning of the operator itself */
 	struct SnapObjectContext *snap_context = ED_transform_snap_object_context_create_view3d(
 	        CTX_data_main(C), CTX_data_scene(C), 0,
 	        CTX_wm_region(C), CTX_wm_view3d(C));
@@ -1038,6 +1041,8 @@ static int sk_getStrokeSnapPoint(bContext *C, SK_Point *pt, SK_Sketch *sketch, S
 		}
 	}
 
+	/* TODO: The ideal would be to call this function only once.
+	 * At the end of the operator */
 	ED_transform_snap_object_context_destroy(snap_context);
 	return point_added;
 }

source/blender/editors/include/ED_transform_snap_object_context.h

@@ -65,10 +65,6 @@ struct SnapObjectParams {
 	unsigned int use_object_edit_cage : 1;
 };
 
-enum {
-	SNAP_OBJECT_USE_CACHE = (1 << 0),
-};
-
 typedef struct SnapObjectContext SnapObjectContext;
 SnapObjectContext *ED_transform_snap_object_context_create(
         struct Main *bmain, struct Scene *scene, int flag);

source/blender/editors/mesh/editmesh_tools.c

@@ -306,7 +306,7 @@ void EMBM_project_snap_verts(bContext *C, ARegion *ar, BMEditMesh *em)
 	ED_view3d_init_mats_rv3d(obedit, ar->regiondata);
 
 	struct SnapObjectContext *snap_context = ED_transform_snap_object_context_create_view3d(
-	        CTX_data_main(C), CTX_data_scene(C), SNAP_OBJECT_USE_CACHE,
+	        CTX_data_main(C), CTX_data_scene(C), 0,
 	        ar, CTX_wm_view3d(C));
 
 	BM_ITER_MESH (eve, &iter, em->bm, BM_VERTS_OF_MESH) {

source/blender/editors/space_view3d/view3d_ruler.c

@@ -280,7 +280,7 @@ static void ruler_state_set(bContext *C, RulerInfo *ruler_info, int state)
 	}
 	else if (state == RULER_STATE_DRAG) {
 		ruler_info->snap_context = ED_transform_snap_object_context_create_view3d(
-		        CTX_data_main(C), CTX_data_scene(C), SNAP_OBJECT_USE_CACHE,
+		        CTX_data_main(C), CTX_data_scene(C), 0,
 		        ruler_info->ar, CTX_wm_view3d(C));
 	}
 	else {

source/blender/editors/space_view3d/view3d_walk.c

@@ -588,7 +588,7 @@ static bool initWalkInfo(bContext *C, WalkInfo *walk, wmOperator *op)
 	walk->rv3d->rflag |= RV3D_NAVIGATING;
 
 	walk->snap_context = ED_transform_snap_object_context_create_view3d(
-	        CTX_data_main(C), walk->scene, SNAP_OBJECT_USE_CACHE,
+	        CTX_data_main(C), walk->scene, 0,
 	        walk->ar, walk->v3d);
 
 	walk->v3d_camera_control = ED_view3d_cameracontrol_acquire(

source/blender/editors/transform/transform_snap.c

@@ -601,7 +601,7 @@ static void initSnappingMode(TransInfo *t)
 	if (t->spacetype == SPACE_VIEW3D) {
 		if (t->tsnap.object_context == NULL) {
 			t->tsnap.object_context = ED_transform_snap_object_context_create_view3d(
-			        G.main, t->scene, SNAP_OBJECT_USE_CACHE,
+			        G.main, t->scene, 0,
 			        t->ar, t->view);
 
 			ED_transform_snap_object_context_set_editmesh_callbacks(